Learning Lab Images in Clinical Medicine

A 31-year-old woman presented with blurred vision and proptosis of the left eye. An MRI revealed a retrobulbar cystic lesion, which was confirmed on histopathological examination to be a hydatid cyst.

A 53-year-old man presented with rapidly progressing lesions on his face and body. A skin biopsy was performed, and a diagnosis of mycosis fungoides with large-cell transformation was made.

A 33-year-old man presented to the emergency department with palpitations. An electrocardiogram showed preexcited atrial fibrillation.

Respiratory distress developed in a male neonate with a giant omphalocele who had been born at 28 weeks of gestation. A “coat hanger” appearance of the ribs was seen on chest radiography.

A 19-year-old man with X-linked retinoschisis presented with worsening vision in his right eye. Examination of the right fundus showed prominent retinal corrugations radiating from the fovea.

A 49-year-old man with human immunodeficiency virus infection presented with ulcerated, violaceous lesions on the penis. Biopsy was performed, and a diagnosis of Kaposi’s sarcoma was made.

A 48-year-old man with end-stage renal disease presented with shortness of breath. Computed tomography of the face revealed mandibular hypertrophy and a heterogeneous appearance of the bone, findings consistent with osteitis fibrosa cystica.

A 29-year-old man with HIV infection presented with abdominal pain and drenching nights sweats. Computed tomography of the abdomen revealed massive splenomegaly caused by disseminated Mycobacterium avium–intracellulare infection.

A 50-year-old man with cirrhosis presented with shortness of breath. Transthoracic echocardiography, shown in a video, revealed opacification of the chambers on the left side of the heart by microbubbles five heartbeats after the appearance of microbubbles in...

A 42-year-old man presented with cough and shortness of breath. Physical examination showed a saddle-nose deformity, and CT showed destruction of the structural bones of the midface that had resulted in the formation of a large nasal cavity. A diagnosis of...

A 62-year-old woman presented with jaundice 3 months after undergoing orthotopic liver transplantation. Imaging revealed filling defects in the bile ducts. During repeat liver transplantation, biliary casts were found and removed (shown in a video).

A 66-year-old man presented with a 4-day history of shortness of breath and swelling in the legs. Transthoracic echocardiography and computed tomography of the chest revealed a mass in the right atrium, and a diagnosis of angiosarcoma was made.

A 42-year-old man presented with a 5-month history of papules along the pattern of his tattoos. A skin biopsy showed noncaseating granulomas.

A 74-year-old woman presented with a long history of bloating and abdominal distention. CT of the abdomen showed multiple fat-containing lesions throughout the small bowel, consistent with intestinal lipomatosis.

A 54-year-old woman presented with progressively worsening gait disturbance. Physical examination revealed persistent leg extension on stimulation of the patellar tendon, shown in a video. A diagnosis of Huntington’s disease was made.

A 73-year-old woman presented with difficulty in speaking. A CT scan of the neck showed a large, sublingual epidermoid cyst.

Physical examination at birth of monochorionic, diamniotic twins born at 31 weeks of gestation showed a pallid first twin and a plethoric second twin. Findings on transabdominal ultrasonography that had been performed at 30 weeks of gestation were suggestive of...

A 53-year-old man presented with fever, dyspnea, and rapidly progressive skin lesions. A biopsy specimen obtained from a lesion showed extranodal natural killer T-cell lymphoma.

A male neonate with Ebstein’s anomaly had respiratory distress immediately after birth. On the third day of life, a clearly demarcated erythema developed on one side of the body, known as harlequin color change.

An 85-year-old man presented with a 2-week history of passing dark stools. Endoscopy revealed multiple polypoid nodules, and a diagnosis of metastatic melanoma was made.

A 57-year-old man received FOLFOX (leucovorin, fluorouracil, and oxaliplatin) as treatment for colon cancer. With treatment, he had progressive hyperpigmentation of the palms of his hands.

A 72-year-old woman presented with weight loss, abdominal pain, and jaundice. Imaging revealed a hepatic hilar mass with marked bilateral biliary ductal dilatation. A diagnosis of cholangiocarcinoma was made.

A 34-year-old man presented with dyspnea and a nonproductive cough. A chest CT showed a crazy-paving pattern. Bronchoalveolar lavage was performed, and a diagnosis of pulmonary alveolar proteinosis was made.

An 81-year-old man with atrial fibrillation who was being treated with amiodarone presented to the ED after a fall. Physical examination revealed blue and gray discoloration of his nose, cheeks, and forehead. This discoloration is associated with amiodarone.

An 84-year-old man had severe pain and weakness in his right arm 7 days after undergoing TAVR. A CT angiogram showed an occlusion of the right axillary artery.

A 19-year-old man presented with an enlarging ulcer on the right hand. A punch-biopsy specimen showed a dense infiltrate of lymphocytes and histiocytes containing leishmania amastigotes.

An 86-year-old woman with a history of severe emphysema presented with shortness of breath. The physical examination revealed diminished breath sounds in the right hemithorax and extensive subcutaneous emphysema, with palpable crepitus in the neck (shown in...

A 19-year-old woman presented with severe abdominal pain. Diagnostic laparoscopy was performed, revealing torsion of the left fallopian tube.

A 38-year-old woman presented with a 6-month history of intermittent hematuria, dysuria, and pelvic pain. Imaging revealed a mass at the bladder dome. Partial cystectomy was performed, and a diagnosis of bladder endometriosis was made.

A 74-year-old woman presented with an acute stroke. The physical examination showed multiple mucocutaneous telangiectasias, and a diagnosis of hereditary hemorrhagic telangiectasia was made.

A 51-year-old right-handed man presented with swelling in the left wrist. MRIshowed rice bodies and culture confirmed invasive mycobacterial tenosynovitisdue to Mycobacterium avium complex.

A 4-year-old girl was brought to the ED after she fell from a tree onto her outstretched hand. Examination revealed deformity of the elbow with bruising and puckering of skin. Radiographs showed a supracondylar fracture.

A 69-year-old woman with rheumatoid arthritis presented for the treatment of severe joint deformities. Examination of the hands, shown in a video, revealed telescoping fingers.

Examination of a 1-day-old baby girl born by vaginal delivery at 36 weeks of gestation revealed a soft mass protruding from the external genitalia. A diagnosis of neonatal hydrocolpos was made.

An 84-year-old woman presented with a rapidly growing nodule on her right hand. Pathological testing showed nodular infiltration of the dermis, and a diagnosis of Merkel-cell carcinoma was made.

A 24-year-old man presented with pain, swelling, and decreased vision in his right eye after it had been struck by a tennis ball. Examination showed a retinal hemorrhage.

A 6-month-old girl whose parents had recently received a diagnosis of syphilis was referred for evaluation after testing suggested that she also had syphilis. Physical examination revealed frontal bossing and a soft-tissue perirectal mass. A biopsy specimen was positive...

A 62-year-old woman who had recently been treated for pelvic inflammatory disease presented with abdominal pain. On laparoscopy, adhesions between the anterosuperior hepatic surface and the abdominal wall were seen, a finding consistent with the...

A 22-year-old man presented with palpitations and chest discomfort. Echocardiography revealed an enlarged, thickened mitral-valve leaflet with systolic prolapse of multiple segments (shown in a video), and a diagnosis of myxomatous mitral-valve prolapse was...

A 76-year-old woman presented to the ED after being struck by a motor vehicle. Anteroposterior radiographs showed lateral dislocation of the right knee.

A 44-year-old man presented to the ophthalmology clinic. Examination revealed circumferential spoke-like iris transillumination defects, and a diagnosis of pigment dispersion syndrome was made.

A 73-year-old woman presented with pruritic and painful lesions on her hands that had an appearance consistent with tripe palms. Computed tomography of the chest was performed, and a diagnosis of metastatic lung cancer was made.

A 40-year-old man presented with fatigue and was found to have anemia and an elevated alkaline phosphatase level. ERCP was performed; a video shows a flatworm emerging from the duodenal papilla.

A 52-year-old man presented with a rapidly growing, bleeding lesion on his right great toe. Excisional biopsy was performed, and a diagnosis of acral lentiginous melanoma was made.

A 70-year-old woman had a urinary catheter placed during hospitalization for an acute stroke. Ten days later, the urine appeared purple.

A 36-year-old woman presented with fever, arthralgias, and a rash on her feet and hands. Blood cultures grew Streptobacillus moniliformis, and a diagnosis of rat bite fever was made.

A 60-year-old woman presented to the emergency department with acute chest pain. Initial electrocardiography was suggestive of posterior-wall ischemia. An ECG performed with the use of posterior leads revealed ST-segment elevation in leads V7, V8, and V9, which...

A 77-year-old woman with limited cutaneous systemic sclerosis presented with painful swelling of her fingertips. A radiograph of the hands showed calcifications.

A 4-year-old girl with juvenile dermatomyositis presented with weakness, rash, and palpable subcutaneous nodules. A radiograph of the pelvis showed extensive soft-tissue calcinosis.

A 64-year-old man presented with a painful, smooth, red tongue and a burning sensation around his lips. Findings on physical examination were consistent with atrophic glossitis, and a diagnosis of pernicious anemia was made.

A 37-year-old man presented to the dermatology clinic with two types of skin lesion. Two types of nevi, both with the same HRAS mutation, were observed in biopsy specimens. A diagnosis of phakomatosis pigmentokeratotica was made.

A 65-year-old woman with a history of lung transplantation who had been receiving long-term prophylaxis with voriconazole presented with progressive swelling in both hands and widespread body pain. Radiographs of the hands showed periostitis.

A 46-year-old woman with rheumatoid arthritis presented with pain and swelling in both knees. Radiographic findings were consistent with synovial chondromatosis.

A 73-year-old man presented with shortness of breath. On ocular exam, pupil dilation and constriction that were synchronized with his heartbeat were noted, a finding known as Landolfi’s sign (shown in a video). He was found to have severe aortic regurgitation.

A 70-year-old woman presented with dizziness, rash, and hemolytic anemia 2 weeks after the onset of a viral respiratory tract infection. The rash was consistent with livedo reticularis, and a diagnosis of cold agglutinin disease was made.

A 14-year-old girl presented with fever, neck swelling, and a grayish-white membrane in the oropharynx. A throat culture grew Corynebacterium diphtheriae.

A 25-year-old woman presented with weakness, fatigue, shortness of breath, and skin discoloration. Her oxygen saturation of 88% did not improve with the use of supplemental oxygen. A diagnosis of methemoglobinemia was made.

A 60-year-old woman with a history of breast cancer presented with blurred vision. Examination revealed proptosis and an inability to look up with the left eye (shown in a video). MRI showed a mass involving the inferior rectus muscle, a finding consistent with a metastatic lesion.

A 29-year-old man with aplastic anemia presented with fever, cough, and a rash with numerous papules, vesicles, pustules, and crusted vesicles. A diagnosis of disseminated varicella infection was made.

A 56-year-old man with a history of radiation therapy to the hands presented with a 2-cm ulcerated lesion on his right palm. Biopsy revealed squamous-cell carcinoma.

A 56-year-old man presented with pain in his right hand after he hit a desk in frustration during an argument at work. A plain radiograph revealed a boxer’s fracture.

A 49-year-old man presented with voice changes and pain with swallowing. Fiberoptic laryngoscopy revealed a laryngeal lesion. Biopsy and imaging were performed, and a diagnosis of metastatic renal-cell carcinoma was made.

During preparation for the transplantation of a kidney into a 9-year-old girl, the donor kidney was found to have five renal arteries.

A 48-year-old man presented to an urgent care clinic with odynophagia and fever. A radiograph of the neck showed the “thumb sign,” and a diagnosis of epiglottitis was made.

A 73-year-old man presented with severe lower abdominal pain. Laparotomy revealed a small-bowel perforation from a fish bone.

An 80-year-old man presented to the emergency department with fever and abdominal pain in the right upper quadrant. Computed tomography revealed emphysematous cholecystitis.

A 32-year-old woman presented with painless hematuria at 24 weeks of gestation. Cystoscopy revealed a bulging posterior bladder wall with extensive vascularization and a focal area of invading chorionic villi, shown in two videos.

A 79-year-old man who had recently undergone transcatheter aortic-valve replacement was admitted with acute kidney injury. Renal biopsy confirmed cholesterol crystal embolization.

A 35-year-old man with a history of hepatosplenic T-cell lymphoma presented with fatigue and pain in the left side of his abdomen. Physical examination and computed tomography revealed massive splenomegaly.

A 56-year-old woman presented with epigastric and left-upper-quadrant abdominal pain. Computed tomography of the abdomen revealed extensive air in the spleen.

A 4-year-old girl presented with headache, nausea, vomiting, and irritability. Magnetic resonance imaging of the brain revealed a cystic mass arising from the tectal plate, with associated hydrocephalus.

A 48-year-old man presented with painful hand ulcerations and progressively worsening shortness of breath. Chest CT revealed organizing pneumonia, and antibody testing confirmed the diagnosis of anti-MDA5 dermatomyositis.

A 63-year-old man with HIV infection presented with a dry cough and exertional dyspnea. Bronchoscopy revealed numerous sessile, friable, wart-like lesions on the posterior wall of the trachea. A diagnosis of respiratory papillomatosis was made.

A 60-year-old man presented with a firm mass on the right side of his neck. Physical examination revealed an enlarged right tonsil, and invasive squamouscell carcinoma was found on biopsy.

A 7-year-old boy presented to the pediatric otolaryngology clinic with multiple firm, slow-growing nodules on the tongue and was found to have an elevated calcitonin level. Genetic testing confirmed a diagnosis of multiple endocrine neoplasia type 2B.

A 41-year-old woman who wore soft contact lenses presented with pain, blurry vision, and sensitivity to light in her left eye. Cultures of corneal scrapings grew Acanthamoeba polyphaga, and a diagnosis of acanthamoeba keratitis was made.

An 8-week-old girl was admitted to the hospital with 2 weeks of worsening cough associated with a whooping sound (shown in a video), along with episodes of apnea. Bordetella pertussis infection was diagnosed.

A 68-year-old man presented with neck swelling, toothache, fever, and difficulty swallowing solids and liquids. A clinical diagnosis of Ludwig’s angina was made.

A two-and-a-half-year-old boy was brought to the emergency department after he had a seizure for which an adult had performed chest compressions and rescue breathing. On arrival, the boy’s abdomen was distended, and a radiograph showed pneumoperitoneum.

A 32-year-old woman presented with anal pruritus and bleeding. Colonoscopy revealed infection with Enterobius vermicularis (shown in a video).

A 72-year-old woman presented with a 2-week history of passing gas in her urine. Cystoscopy revealed an area of edematous bladder mucosa with a central orifice that extruded gas and feculent material (shown in a video), and a diagnosis of a colovesical fistula was made.

A 68-year-old woman presented to the otorhinolaryngology clinic with swelling in the neck and progressive discomfort during swallowing. She had a mobile, soft, and nontender mass in the midline of her neck that was consistent with a thyroglossal duct cyst.

A 17-year-old boy presented to the ED with pain and swelling in his jaw 2 hours after an e-cigarette exploded during use. He had extensive lacerations in his mouth, multiple disrupted lower incisors, and bony incongruity of his left mandible.

A 48-year-old man presented with pain in both flanks and weight loss. Numerous splinter hemorrhages were observed on the fingernails. A diagnosis of nonbacterial thrombotic endocarditis was made.

A 64-year-old man presented with fatigue and dizziness. A peripheral-blood smear showed mature lymphoid cells with cytoplasmic blebs, and a diagnosis of T-cell prolymphocytic leukemia was made.

A 66-year-old man presented with cough and pain in his chest and on the left side of his abdomen. Physical examination and imaging revealed situs inversus totalis.

A 34-year-old man with HIV infection presented with headache, fever, confusion, and a large tongue lesion. Fungal organisms were identified on biopsy, and a diagnosis of disseminated coccidioidomycosis was made.

A 76-year-old man who had previously worked as a sandblaster presented with progressively worsening dyspnea. Findings on chest imaging were consistent with chronic silicosis with progressive massive fibrosis.

An 84-year-old man presented with weakness and shortness of breath. Electrocardiographic results aroused concern about an ST-segment elevation myocardial infarction. Imaging of the chest 1 month earlier had revealed a large mass invading the left ventricle.

A 47-year-old man with known IgG4-related disease presented to the cardiology clinic. Cardiac imaging revealed aneurysmal dilatation of the right coronary artery with marked periarterial soft-tissue thickening.

A 2-year-old girl presented with perianal itching and worms in the stool. She was found to have a Dipylidium caninum infection.

A full-term infant had bilious emesis and failure to pass meconium in the first 24 hours of life. Findings on water-soluble contrast enema were consistent with total colonic aganglionosis.

A 60-year-old man presented with worsening nasal obstruction and postnasal drip. Nasopharyngoscopy showed a smooth, pink, cystic mass in the midline of nasopharynx, consistent with Tornwaldt’s cyst.

A 51-year-old woman with autosomal dominant polycystic kidney disease presented with chronic abdominal pain. Magnetic resonance cholangiopancreatography revealed numerous cysts throughout the liver.

A 66-year-old man presented with abdominal bloating. The physical examination was notable for a pulsatile abdominal mass (shown in a video). Imaging revealed a large infrarenal aortic aneurysm.

A 59-year-old woman presented with inflammation and pain in the right eye. Magnetic resonance imaging showed a right orbital mass. A diagnosis of metastatic uveal melanoma was made.

A 37-year-old man presented with excessive sweating, headaches, and increasing skin folds on his scalp. MRI showed a pituitary adenoma, and a diagnosis of acromegaly was made.

A 9-year-old boy reported hearing buzzing noises and having a sensation of a foreign body in the right ear. A tick was found embedded in his right tympanic membrane.

A 57-year-old woman receiving long-term hydroxychloroquine treatment presented for ophthalmic evaluation. Achromatic perimetry revealed paracentral scotomas in each eye, and optical coherence tomography revealed a loss of the retinal inner and outer segments.

A 60-year-old woman receiving long-term hydroxychloroquine presented to the eye clinic after noticing central blind spots in her visual fields. Retinal examination showed a bull’s-eye pattern of hypopigmentation.

A 20-year-old woman presented with erythematous pustules on her arms and legs and joint pain in both ankles. Blood cultures were positive for Neisseria gonorrhoeae.

A 35-year-old man presented with a 2-day history of abdominal pain and headache. A peripheral-blood smear showed numerous schistocytes, and a diagnosis of thrombotic thrombocytopenic purpura was made.

A 14-year-old boy was admitted with a severe asthma exacerbation. A chest radiograph showed pneumomediastinum with diffuse subcutaneous emphysema. As his respiratory status improved, swelling and palpable crepitus developed in both cheeks and the right eyelid.

A 48-year-old man presented with eye pain and iris deformity after he was struck in the left eye by a rubber bungee cord. A diagnosis of traumatic iridodialysis was made.

A 27-year-old man presented with a red, granular, pedunculated, nonpulsatile mass that obstructed the right nasal cavity. Surgical excision was performed, and a diagnosis of rhinosporidiosis was made.

A 10-year-old girl presented with multiple itchy papules with central black dots on the soles of her feet. Sand fleas were removed from the lesions, and a diagnosis of tungiasis was made.

A 61-year-old woman presented with acute abdominal pain. Computed tomography of the abdomen revealed free air and extraluminal gas in the bowel wall. Emergency laparotomy was performed.

An 18-year-old man presented to the emergency department with generalized tonic–clonic seizures. MRI of the head showed numerous well-defined cystic lesions in the brain that were consistent with cysticercosis.

An 18-year-old man presented with a sore throat, fever, and pleuritic chest pain. Neck CT revealed a thrombus of the right internal jugular vein, and a blood culture grew Fusobacterium necrophorum.

A 47-year-old woman with metastatic melanoma presented with progressive discoloration of the skin, nails, and oral mucosa and with melanuria.

A 30-year-old man with HIV infection presented with fever and bloody diarrhea. A peripheral-blood sample showed myeloid cells with intracytoplasmic yeast-like forms. A diagnosis of disseminated histoplasmosis was made.

A 73-year-old woman presented to the emergency department with a painful umbilical nodule. Computed tomography of the abdomen and pelvis revealed a large pelvic mass, and a diagnosis of ovarian cancer was made.

Two brothers returned from travel to sub-Saharan Africa with fever, headache, and multiple eschars. A diagnosis of African tick-bite fever was made.

A 9-year-old girl presented to clinic with sore throat and fever. “Doughnut” lesions were seen on the palate, and throat culture confirmed infection with group A beta-hemolytic streptococcus.

Surveillance with FDG-PET performed in a 61-year-old woman with a history of melanoma showed two cardiac masses. The biopsy specimen revealed metastatic melanoma.

A 54-year-old man presented with difficulty chewing food. He had a painless brown lesion growing in the center of a white patch on the right side of the tongue. Biopsy revealed spindle-cell sarcoma.

A 10-year-old girl presented with headache and poor growth. Laboratory studies showed primary hypothyroidism, and MRI revealed an enlarged pituitary.

A 65-year-old farmer presented with a progressively enlarging annular rash over the right hand and forearm. Biopsy was performed, and fungal culture grew Sporothrix schenckii.

A 3-year-old girl was brought to the emergency department after she ingested a metal pendant. A radiograph of the chest showed a heart-shaped pendant in the esophagus.

A 64-year-old man presented with shortness of breath and swelling of the right calf. Computed tomography of the chest showed thrombus in the right and left pulmonary arteries, and echocardiography showed a thrombus in the right ventricle (shown in a video).

A 31-year-old man who had recently received a diagnosis of erythema nodosum presented to an outpatient clinic with recurrent oral and genital ulcers. A diagnosis of Behçet’s disease was made.

A 53-year-old man with a history of kidney and liver transplantation presented with enlarging nodules on his scalp. On biopsy, Michaelis–Gutmann bodies were identified, and cultures grew Escherichia coli and Pseudomonas aeruginosa. A diagnosis of malakoplakia was made.

A 5-year-old girl presented with a 2-year history of excessive head nodding. MRI of the head revealed a suprasellar arachnoid cyst and ventriculomegaly. A video shows the child displaying movements typical of the bobblehead-doll syndrome.

A 45-year-old man presented with abdominal pain and vomiting. He had abdominal tenderness and hyperpigmented macules on the lips, oral mucosa, and nose. Emergency laparotomy revealed jejunojejunal intussusception and multiple polyps. A diagnosis of the Peutz–Jeghers syndrome was made.

A 41-year-old woman presented to the ophthalmology clinic with vision that had been deteriorating during the preceding 20 years. Slit-lamp examination revealed multiple corneal incisions, a finding consistent with a history of radial keratotomy.

A 49-year-old man presented with fever, abdominal pain, and unintentional weight loss. He had an enlarged liver and spleen, and examination of a bone marrow aspirate revealed amastigotes. A diagnosis of visceral leishmaniasis was made.

A 73-year-old woman presented with an evolving pruritic, erythematous rash and was found to have anal cancer. A diagnosis of erythema gyratum repens was made.

A 37-year-old woman at 27 weeks of gestation presented for routine fetal ultrasonography, which revealed fetal blood vessels covering the internal cervical os. Cesarean delivery at 34 weeks was performed for vasa previa.

A 2-week-old baby presented with purulent discharge from both eyes. An eyedischarge sample from the baby and a maternal endocervical swab both tested positive for Chlamydia trachomatis.

A 32-year-old man presented with recurrent dysphagia caused by food impaction. Endoscopy revealed trachealization of the esophagus, and a diagnosis of eosinophilic esophagitis was made.

A 76-year-old man with a history of heart failure presented with shortness of breath and fever 9 months after transcatheter aortic-valve replacement. Blood cultures grew Candida parapsilosis. A video shows findings of prosthetic-valve endocarditis on echocardiography.

A 29-year-old man presented with an erythrodermic, papulosquamous rash. A punch biopsy confirmed erythrodermic psoriasis. Evaluation for an underlying cause led to a diagnosis of HIV infection.

A 24-year-old man presented with progressive dysphagia, dysarthria, and weakness in his arms and legs. The physical examination showed jaw clonus and muscle fasciculations (shown in a video), consistent with a diagnosis of amyotrophic lateral sclerosis.

An 84-year-old main presented with discoloration and pain in the fingers and toes that had progressed over a 2-week period. Biopsy findings were consistent with a medium-vessel vasculitis.

A 46-year-old man with a prior gunshot wound to the left knee presented with worsening knee pain. Radiographs showed fragmentation of the bullet into innumerable metallic particles.

An 18-year-old man with a history of Kawasaki’s disease and known coronary artery aneurysms presented with chest pain. Coronary angiography revealed occlusion of the left anterior descending artery.

A 73-year-old man presented to the clinic with a generalized rash and was found to have a pulmonary nodule. A diagnosis of paraneoplastic erythroderma was made.

A 67-year-old woman with a history of a lung transplantation presented with dyspnea on exertion and a hemoglobin level of 6.7 g per deciliter. Bone marrow aspiration revealed giant proerythroblasts. PCR testing confirmed parvovirus B19 infection.

A 29-year-old man with HIV presented with fever and abdominal pain. Computed tomography of the abdomen revealed a ring-enhancing hepatic lesion, and a polymerase-chain-reaction assay of stool confirmed infection with Entamoeba histolytica.

A 58-year-old man presented with a slowly enlarging mass on the left side of the neck. The mass increased in size when the Valsalva maneuver was performed, and laryngoscopic examination revealed partial obstruction of the airway lumen (shown in videos).

A 28-year-old man presented with nail pitting and skin plaques on the extensor surfaces of both elbows and knees. A diagnosis of psoriasis was made.

A 36-year-old man was admitted to the intensive care unit with an acute exacerbation of chronic heart failure. After a ventricular assist device was placed and anticoagulation therapy initiated, hemoptysis developed, and he expectorated a cast of the right bronchial tree.

A 72-year-old man presented with an 11-hour history of periumbilical abdominal pain and inability to pass flatus. Computed tomography revealed extensive portal venous gas.

A 64-year-old man with asplenia presented with confusion, fever, and headache. Gram’s stain of the blood and CSF revealed abundant gram-positive cocci in pairs and chains.

A 70-year-old woman presented with a 2-month history of shortness of breath and wheezing. Bronchoscopy revealed a pigmented endobronchial mass (shown in a video) that was consistent with melanoma.

A 56-year-old woman with no history of smoking presented with shortness of breath that had progressively worsened over 8 months. CT revealed diffuse pulmonary nodules. Non–small-cell lung cancer with an EGFR mutation was diagnosed.

A 51-year-old woman presented to the emergency department after ingesting 30 packs of opium. Computed tomographic scans of the abdomen and pelvis suggested lead contamination of the ingested packs.

A 39-year-old man presented with abdominal pain and constipation. Physical examination revealed a gray line along the margins of the lower gums. Evaluation confirmed an elevated blood lead level.

A 5-year-old girl who frequently played with a cat presented with an eyelid papule and preauricular and submandibular masses on the left side of her face. A diagnosis of cat scratch disease was made.

A 52-year-old man presented to the emergency department with painless, bloody tears. Slit-lamp examination revealed hemangiomas on the inside of both eyelids.

A 62-year-old man presented with low back pain, fevers, chills, night sweats, and weight loss. MRI revealed spondylitis and large psoas abscesses. Cultures grew Brucella melitensis.

A 35-year-old man presented with patchy, irregular alopecia of the scalp and a faint, erythematous rash on his trunk and his arms and legs. A diagnosis of secondary syphilis was made.

A 47-year-old woman presented with exertional dyspnea and orthopnea. Echocardiography revealed a mass attached to the interatrial septum, with partial prolapse into the left ventricle obstructing mitral-valve inflow (shown in a video). Atrial myxoma was diagnosed.

A 42-year-old man undergoing treatment for non-Hodgkin’s lymphoma presented with changes in his fingernails. Physical examination showed brown discoloration of his fingernails and two types of transverse white lines that were not palpable.

A 45-year-old man with primary hyperparathyroidism due to parathyroid carcinoma presented with pain in his left forearm. Imaging revealed a radial fracture and a diffusely low-density, mottled appearance of the radius and ulna.

A 32-year-old man with a family history of neurofibromatosis type 2 presented with balance difficulties and hearing loss. Magnetic resonance imaging revealed bilateral vestibular schwannomas.

A 53-year-old man presented to the endocrinology clinic with fatigue and sensitivity to cold. A physical examination showed delayed relaxation of the ankle jerk reflex — Woltman’s sign, shown in a video — and laboratory evaluation confirmed a diagnosis of primary hypothyroidism.

A 41-year-old woman presented to an outpatient clinic with nail changes that had occurred over several months and hair loss that had progressively worsened over 2 years. A diagnosis of Hashimoto’s thyroiditis was made.

A pregnant 35-year-old woman underwent routine fetal ultrasonography that revealed ventriculomegaly. After delivery, testing confirmed congenital CMV infection in the newborn.

A 26-year-old man presented with symptoms of a respiratory infection, and severe mucositis developed over the subsequent 3 days. Polymerase-chainreaction and serologic tests confirmed infection with Mycoplasma pneumoniae.

A 24-year-old man presented to the emergency department with abdominal pain and distention. Exploratory laparoscopy was performed, and tuberculous peritonitis was diagnosed.

A 42-year-old woman with systemic lupus erythematosus presented with swelling and pain in her left fifth finger. Biopsy revealed acid-fast bacilli, and tissue cultures for Mycobacterium tuberculosis were positive.

A 58-year-old man presented with a chronic productive cough. Imaging and lung biopsy confirmed the diagnosis of disseminated actinomycosis.

A 63-year-old man presented with cough and a history of recent weight loss of 10 kg. Computed tomography revealed a 5.6-cm mass in the right lower lobe and a pack of cigarettes and a lighter in his right breast pocket. A diagnosis of squamous-cell carcinoma was made.

A 68-year-old man presented with progressive, painful neck swelling. A diagnosis of glandular tularemia was made.

A 55-year-old woman started treatment with meropenem and minocycline for a polymicrobial infection. Within 1 week, she had tongue discoloration that was consistent with black hairy tongue.

A 54-year-old woman presented with fatigue, intermittent hemorrhoidal bleeding, and spoon-shaped nails. Iron-deficiency anemia and koilonychia were diagnosed.

A 4-year-old boy presented to the ophthalmology clinic with poor night vision and enlarging white deposits in both eyes. A diagnosis of Bitot’s spots due to vitamin A deficiency was made.

A 31-year-old man with cirrhosis presented with confusion and anemia. A peripheral blood smear showed numerous spur cells.

A 54-year-old woman presented for a routine eye examination and was found to have multiple sparkling opacities in the left eye (shown in a video), a finding consistent with asteroid hyalosis.

A 39-year-old man with end-stage renal disease presented with diffuse crystalline white deposits across his skin, a finding consistent with uremic frost.

A newborn baby had copious oral secretions. A nasogastric tube was inserted but met resistance at the T2 level. Esophageal atresia with tracheoesophageal fistula was diagnosed.

A 4-year-old boy presented to the otorhinolaryngology outpatient clinic with a 2-day history of a whistling cough, shown in a video. Bronchoscopy was performed, and an aspirated toy whistle was retrieved.

A 69-year-old man presented to the dermatology clinic with a 2-month history of a pruritic rash on his trunk, arms, and legs. Biopsy of a lesion confirmed lichen planus.

A 58-year-old man with a bioprosthetic aortic valve presented with exertional dyspnea. Videos show rapidly declining pulsation of the right carotid artery and capillary pulsation of the index finger, thumb, and nail bed, findings suggestive of severe aortic regurgitation.

A 4-week-old boy was brought to the ED after 2 days of drainage in both eyes and 1 day of redness and swelling under his left eye. Acute dacryocystitis was diagnosed.

A 71-year-old man with a 5-year history of ulcerative colitis presented with ulcerative lesions on the chest and leg consistent with pyoderma gangrenosum.

A 71-year-old man presented to the emergency department with fever and left hand pain after eating raw seafood. Surgical wound cultures identified Vibrio vulnificus.

A 36-year-old man presented to the emergency department with a 2 week-history of headache, photophobia, and fever. Gram’s staining and India ink staining of the cerebrospinal fluid revealed encapsulated yeast, and C. neoformans was identified on culture.

A 47-year-old man presented with progressive dyspnea on exertion and was found to have very severe mitral-valve stenosis and a markedly enlarged left atrium (shown in a video).

A 35-year-old woman presented with weakness in both legs that had progressed over 3 months. Spinal MRI revealed a vertebral lesion, and echinococcus was identified on surgical excision.

A 30-year-old man from Morocco presented with right upper abdominal discomfort. Findings on imaging were consistent with hydatid cysts.

A 44-year-old man presented to the dermatology clinic with crusted skin lesions. A skin biopsy and staining confirmed a diagnosis of disseminated cutaneous blastomycosis.

An 89-year-old man presented for evaluation of an inguinal hernia and was found to have marked abdominal-wall varices. Imaging revealed occlusion of the superior vena cava.

A 4-month-old girl was hospitalized with failure to thrive, hepatosplenomegaly, anemia, and hyperlipidemia. Radiography revealed calcification of both adrenal glands. A diagnosis of lysosomal acid lipase deficiency was made.

An 86-year-old woman presented with fatigue and headache. Temporal-artery biopsy confirmed a diagnosis of giant-cell arteritis. Several days later, she returned with tongue necrosis. Computed tomography revealed thrombosis of the right lingual artery.

A 32-year-old woman presented to an ophthalmologist with a 2-week history of nodules that moved around her face. Dirofilaria repens was surgically removed.

A 9-year-old boy presented with decreased vision in his left eye after gazing into the beam of a laser pointer. Funduscopy and optical coherence tomography revealed a full-thickness macular hole.

A 63-year-old man presented with abdominal pain in the left lower quadrant. Computed tomography showed thumbprinting of the sigmoid colon, and laparotomy confirmed a diagnosis of ischemic colitis.

A 78-year-old man presented with enlargement and stiffening of the tongue. Biopsy confirmed that this finding of macroglossia was due to light-chain amyloidosis.

A 49-year-old man with hypertension was referred for evaluation of recurrent angina. Coronary angiography revealed a large aneurysm (shown in a video) in the left main coronary artery.

A 44-year-old woman presented with chest pain. She was found to have a large pneumothorax and diffuse intraparenchymal pulmonary cysts that were consistent with lymphangioleiomyomatosis.

A 33-year-old pregnant woman was admitted for delivery at 41 weeks. Severe vulvovaginal varicosities were seen.

A 77-year-old man presented to the endocrinology clinic with a goiter and facial congestion that occurred after he elevated both arms, a reaction that was consistent with Pemberton’s sign (shown in a video).

A newborn with large, annular scalp lesions was brought to the pediatrician. A trichophyton species was identified, and tinea capitis was diagnosed.

A 25-year-old woman with Takayasu’s arteritis presented to the ophthalmology clinic with gradual, painless loss of vision in both eyes that was suggestive of retinal vasculitis. Retinal blood flow before and after treatment is shown in videos.

A 46-year-old man presented to the ED with shortness of breath, low back pain, and weight loss. Radiography revealed a “raindrop skull” appearance. A diagnosis of multiple myeloma was confirmed.

A 29-year-old woman presented with fever, dyspnea, and hypotension and was found to have a large pericardial effusion with extensive fibrin strands (shown in a video). A diagnosis of tuberculous pericarditis was made.

A 49-year-old man with severe hypercholesterolemia and a history of biliary cirrhosis presented with painful xanthoma striatum palmare, which abated after weekly LDL apheresis.

A 31-year-old man with HIV infection presented with headache, confusion, and gait instability. MRI of the brain revealed a large abscess resulting from reactivation of Trypanosoma cruzi.

A 31-year-old man presented to the ED with swelling of the left ear and a saddle-nose deformity. A diagnosis of relapsing polychondritis was made.

A 78-year-old man presented to the ED after a choking episode. CT revealed an inhaled chicken bone.

A 61-year-old man presented with retro-orbital pain, near-complete ophthalmoplegia, loss of vision, and facial sensory deficits. Ophthalmologic findings are shown in a video.

A 74-year-old woman presented with abdominal pain, nausea and vomiting, and inability to pass stool. Imaging revealed the colon cutoff sign.

A 36-year-old man presented to the ED with chest discomfort and electrocardiographic changes suggestive of an occlusion of the proximal left anterior descending coronary artery.

A 70-year-old man who was receiving long-term minocycline treatment presented with blue discoloration of the sclerae. Minocycline-induced pigmentation was diagnosed.

A 28-year-old woman who had had deep venous thrombosis and pulmonary embolus 10 years earlier presented with flank pain and was found to have multiple struts from an inferior vena cava filter that had embolized to the abdomen and right ventricle.

A 21-year-old woman presented with pain and swelling in the right leg and was found to have chondroblastic osteosarcoma with extensive pulmonary metastases.

A 36-year-old man presented to a dermatology clinic with tongue lesions and blisters on his palms and soles. Hand, foot, and mouth disease was diagnosed.

A 57-year-old woman presented with nausea and vomiting and was found to have a gallstone in the proximal duodenum, which caused gastric outlet obstruction.

A 5-year-old girl presented to the emergency department with pruritic and ulcerated lesions on both legs. Skin culture revealed Corynebacterium diphtheriae.

A 45-year-old man presented to the emergency department with abdominal pain in the right lower quadrant. An appendectomy was performed, and the parasite Enterobius vermicularis was found in the appendix.

In a newborn infant with a prenatal diagnosis of cystic fibrosis, abdominal distention and emesis developed at 12 hours of age. A radiograph of the abdomen and a water-soluble contrast enema suggested a diagnosis of meconium ileus.

A 27-year-old man presented with fevers, night sweats, weight loss, and a painful, pulsatile hand lesion that was found to be a mycotic aneurysm of the ulnar artery.

A 59-year-old man with a history of bipolar disorder was admitted to the hospital after a fall and was incidentally found to have numerous small renal cysts, a finding consistent with previous lithium treatment.

A 13-year-old boy presented to an orthopedic clinic with knee pain. A physical examination revealed tenderness over the right tibial tubercle. Radiographs showed characteristic findings of Osgood–Schlatter disease.

A 52-year-old woman presented to the ED with eye pain, blurred vision, and an elevated intraocular pressure, findings consistent with acute angle-closure glaucoma.

A 73-year-old woman with diabetes and recurrent urinary tract infection presented with fever and lethargy. CT revealed an enlarged kidney with staghorn calculus, cortical atrophy, and calyceal dilatation. After nephrectomy, xanthogranulomatous pyelonephritis was diagnosed.

A 24-year-old woman presented to the ophthalmology clinic with visual changes and photophobia. Inflammation and crystalline deposits on the corneal stroma were consistent with interstitial keratitis.

A 19-year-old woman presented to the emergency department with lower abdominal and pelvic pain. Physical examination revealed a suprapubic mass and imperforate hymen, findings consistent with hematometrocolpos.

A 42-year-old woman who had had two previous cesarean sections presented to the primary care clinic with a history of lower abdominal bloating. Retained surgical sponges were identified.

An 81-year-old man presented to the emergency department with acute pain and swelling of the left leg. He was found to have extensive deep venous thrombosis in the leg and acute compartment syndrome.

A 24-year-old man presented to the otolaryngology clinic with a recurrent neck abscess. Imaging revealed that the abscess was due to a sinus created by a branchial-cleft remnant.

A 1-year-old girl was admitted to the hospital with 4 days of fever, erythema, and swelling of a finger. The analysis of an oral lesion was positive for herpes simplex virus type 1, confirming a diagnosis of herpetic whitlow.

A 76-year-old woman was brought to the emergency department with severe hypothermia and was found to have Osborn waves and other electrocardiographic findings that resolved with rewarming.

A 69-year-old woman presented to the emergency department with gross hematuria. Cystoscopic examination of the bladder (shown in a video) revealed a papillary mass protruding through the ureteral orifice with ureteral peristalsis.

A 54-year-old man presented to the emergency department with a 3-week history of cognitive decline. Imaging and cerebrospinal fluid markers were consistent with Creutzfeldt–Jakob disease.

A 35-year-old man presented with a history of hemoglobin Sβ thalassemia and recurrent episodic abdominal pain. A calcified spleen was revealed on imaging.

A 66-year-old woman presented with a 2-week history of cough as well as bruising and pain across the right flank. Nasopharyngeal culture confirmed infection with Bordetella pertussis, and imaging revealed a rib with a displaced fracture.

An 83-year-old woman presented to the emergency department with weakness, slurred speech, and urinary incontinence. MRI showed a symmetric, bifrontal lesion that extended across the corpus callosum and resembled a butterfly. A biopsy was performed and glioblastoma was diagnosed.

A 25-year-old woman with recently diagnosed bacterial endocarditis and a history of intravenous drug use presented with pain and redness in her right eye and was found to have an iris abscess.

A 1-year-old girl was admitted to the hospital with 4 days of fever, erythema, and swelling of a finger. The analysis of an oral lesion was positive for herpes simplex virus type 1, confirming a diagnosis of herpetic whitlow.

An 11-year-old girl presented with a necrotic-appearing ulceration on her left cheek that had been present for 3 weeks. Evaluation confirmed infection with cowpox virus.

A 33-year-old man with fever, lethargy, and hypoxemia received a diagnosis of influenza A infection. Pneumomediastinum and opacities in both lungs were seen on chest imaging.

An 86-year-old man presented to the dermatology clinic for a routine examination and was noted to have an absent right pectoralis major muscle and brachydactyly of the right hand — findings consistent with the Poland syndrome.

A 70-year-old woman presented with a 2-year history of gait disturbance, urinary incontinence, and cognitive impairment and had imaging findings of normalpressure hydrocephalus. Videos show gait improvement after the placement of a ventriculoperitoneal shunt.

A 29-year-old man presented with 2 months of fever, cough, dyspnea, and weight loss. Biopsy of extensive cutaneous lesions revealed Talaromyces marneffei.

An 87-year-old man presented with a 3-week history of nausea, emesis, anorexia, and weight loss. Upper endoscopy identified three pigmented lesions, and melanoma was confirmed on biopsy.

A 27-year-old man presented with a 2-year history of recurrent, painful skin lesions. A diagnosis of hidradenitis suppurativa was made.

A 23-day-old male infant presented with nonbilious vomiting. Physical examination of the abdomen revealed a possible mass, and imaging showed the “caterpillar” sign, which is suggestive of pyloric stenosis.

A 3-year-old boy presented with postprandial abdominal pain and vomiting. Abdominal imaging showed a large burden of tubular structures filling the small bowel, a finding consistent with infection with Ascaris lumbricoides.

A 21-year-old woman with acute myeloid leukemia who was undergoing induction chemotherapy presented with a lesion on her left knee. Blood and wound cultures grew Pseudomonas aeruginosa, and a diagnosis of ecthyma gangrenosum was made.

A 48-year-old woman with a prolonged history of glucocorticoid use presented with abdominal fullness. Computed tomography showed numerous gascontaining cysts within the colonic wall.

A 67-year-old man with an 8-month history of dysphagia and regurgitation presented to the gastroenterology clinic. A barium swallow examination showed an outpouching esophageal lesion consistent with a Zenker’s diverticulum.

A 53-year-old man with psoriasis presented to the dermatology clinic with new psoriatic lesions on his chest where electrodes had recently been placed during electrocardiography.

A 42-year-old woman presented to the dermatology clinic with rapidly progressive, painful gingival hyperplasia. Clinical and laboratory findings were consistent with granulomatosis with polyangiitis.

A 7-year-old boy with a history of atopic dermatitis presented to the dermatology clinic with a 3-month history of widespread flesh-colored papules over the chest and axilla. A clinical diagnosis of molluscum contagiosum was made.

A 79-year-old man presented with a large bulge on his upper arm that developed when he was lifting an object. This finding on physical examination, known as the Popeye sign, suggested rupture of the biceps tendon.

An 87-year-old woman presented to the emergency department with abdominal distention, pain in the epigastrium, and watery diarrhea. Abdominal imaging revealed the falciform ligament sign, which is associated with pneumoperitoneum. 

A 58-year-old woman had a history of medical and acupuncture treatment for rheumatoid arthritis. Plain radiographs of the hands showed severe joint deformities, with short gold threads surrounding the joints.

A 26-year-old man presented with compartment syndrome after prolonged immobilization of his left arm. Delayed decompression restored perfusion to ischemic muscles.

A 48-year-old-man presented with whitish discoloration and hyperkeratosis of the toenail that had extended quickly from the proximal to the distal nail fold. This atypical presentation of onychomycosis prompted investigation for underlying immunosuppression. 

A 62-year-old woman presented with stiffness of the left nipple. Palpation, mammography, and ultrasonography were normal. However, a 5-mm pigmented macule was noted on the left areola. Biopsy revealed invasive adenocarcinoma.

A baby girl was delivered by cesarean section at 36 weeks of gestation because of an antenatal diagnosis of congenital diaphragmatic hernia.

An 11-year-old boy presented to the emergency department with severe nasal pain. Radiographs of the face showed attracting magnets across the nasal septum.

A 42-year-old man presented to the emergency department with skin changes, arthralgias, and vomiting after scuba diving. He was treated for decompression sickness.

A 61-year-old woman presented to the emergency department with chest pain. ST-segment elevations were revealed on ECG. A coronary angiogram showed normal coronary arteries, but left ventriculography and echocardiography, shown in videos, revealed takotsubo cardiomyopathy.

An 80-year-old man presented to the emergency department after a fall at home. Serum studies demonstrated an anion and osmolal gap. Examination of the urine sediment showed calcium oxalate monohydrate crystals, suggestive of ethylene glycol toxicity.

A 59-year-old man with trichilemmomas, acral keratosis, and macrocephaly presented for dermatologic evaluation. Clinical evaluation led to genetic testing, which revealed a mutation in the gene encoding the tumor suppressor PTEN.

A 65-year-old man presented with a 6-week history of severe itching in the inguinal area. A crab-shaped parasite moving along a pubic hair was revealed by dermoscopy and is shown in a video.

A 63-year-old woman presented to the emergency department with a 2-day history of hematemesis and black stool. Esophagogastroduodenoscopy revealed a black esophagus with ulcerated longitudinal necrosis — findings that were consistent with acute esophageal necrosis.

A 31-year-old woman receiving total parenteral nutrition after small-bowel resection presented with progressive exertional dyspnea. CT and lung biopsy confirmed a diagnosis of pulmonary foreign-body granulomatosis due to parenteral injection of oral opiates. 

A 35-year-old man presented with sharp neck pain and a foreign-body sensation in the throat. Computed tomography showed elongated styloid processes, and a diagnosis of Eagle’s syndrome was made.

A 54-year-old woman who regularly chewed loose-leaf tobacco presented with swelling, soreness, and an indurated lesion in the floor of the mouth. A biopsy confirmed squamous-cell carcinoma.

A 17-year-old boy from a rural town in Mexico presented with decreased visual acuity and pain in his right eye. Slit-lamp examination, shown in a video, revealed an intraocular infection with a trematode.

A 65-year-old woman presented to a clinic to be evaluated for Marfan’s syndrome after her identical twin received a diagnosis of the disorder. A video shows iridodonesis, or “dancing” of the iris, which was revealed in an eye examination.

A 41-year-old man presented with progressive loss of vision in both eyes. He also had elongated digits and pectus excavatum. Evaluation revealed ectopia lentis, which is consistent with Marfan’s syndrome.

A 67-year-old man presented 12 hours after the onset of chest pain. During emergency coronary angiography, his condition became hemodynamically unstable. Left ventriculography, shown in a video, revealed rupture of the leftventricular free wall.

A 64-year-old man with a history of an orthotopic neobladder construction presented to the emergency department with a 3-day history of flank pain and urinary retention. Imaging revealed an obstructing stone in the left ureter and a large stone in the neobladder.

A 6-year-old girl was brought to the emergency department with sudden onset of weakness in the left arm and leg. Physical examination and MRI suggested a diagnosis of the Sturge–Weber syndrome.

A 43-year-old woman presented with chronic cough. Bronchoscopy and biopsy revealed evidence of eosinophilic bronchitis.

A 57-year-old man presented with signs and symptoms of mesenteric ischemia. An intraoperative video shows the presence of air in the mesenteric veins with venous pulsation.

A 52-year-old woman who was taking immunosuppressive therapy for rheumatoid arthritis presented with a 1-month history of painful plaques on both palms. Biopsy findings were consistent with Sweet’s syndrome.

A 21-year-old man with refractory acute myeloid leukemia presented with itching and tearing in both eyes 1 month after hematopoietic stem-cell transplantation. A diagnosis of acute ocular graft-versus-host disease was made.

An 8-year-old girl with atopic dermatitis presented with a diffuse eruption of pruritic, umbilicated, erythematous vesicles. Direct fluorescent antibody testing was positive for herpes simplex virus type 1.

A 34-year-old man with situs inversus presented with fever and cough. A radiograph of the chest confirmed the presence of left-middle-lobe pneumonia.

A 76-year-old man with long-standing type 2 diabetes presented with painless, rubbery, hyperpigmented masses on his abdomen. A diagnosis of insulinmediated lipohypertrophy was made.

Two brothers presented to a primary care clinic with similar skin lesions and were found to have elevated LDL cholesterol levels. Family history helped make a diagnosis of familial hypercholesterolemia.

A 71-year-old man presented with severe diffuse pruritus. A diagnosis of crusted scabies was made by physical examination and microscopy.

A 60-year-old man presented with a fever and was found to have abundantsmall, round, calcified gallstones.

A 28-year-old woman who had recently had hyperemesis gravidarum presented with confusion and falls. She was found to have nystagmus (shown in videos) and MRI abnormalities consistent with Wernicke’s encephalopathy.

A 68-year-old woman presented with fever, shortness of breath, and wheezing. Computed tomography revealed an obstructing broncholith and postobstructive pneumonia.

A 25-year-old woman who had undergone orthotopic heart transplantation presented with a 4-year history of severe warts on both her feet. After debulking surgery, these lesions gradually disappeared during treatment with cidofovir.

An 85-year-old woman with essential thrombocytosis and coronary artery disease presented to the ED with abdominal pain. CT of the abdomen and gated aortic MRI revealed four intraaortic thrombi, shown in a video

A 31-year-old man presented with shortness of breath and abnormal skin changes. Examination of the skin revealed a salt-and-pepper appearance.

A 27-year-old woman presented with a drooping left eyelid. A video shows that manual elevation of the left eyelid induced ptosis of the right eyelid.

A 59-year-old man presented with a 1-year history of progressively worsening headaches. Imaging revealed multiple lesions, and genetic analysis confirmed a diagnosis of the familial cerebral cavernous malformation syndrome.

A 66-year-old woman presented with sudden-onset pain and bruising in her right middle finger. She had had a similar episode 3 weeks earlier, which had resolved spontaneously.

A 44-year-old man presented with pain and decreased vision in both eyes after an injury he sustained while lighting a firecracker. Examination and imaging revealed globe rupture and multiple foreign bodies embedded in the corneal stroma.

A 69-year-old woman with chronic kidney disease and myelofibrosis presented with dyspnea and weakness. Imaging revealed lesions in both perirenal spaces, and extramedullary hematopoiesis was detected on biopsy.

A 52-year-old man presented with episodic chest pain. Videos show results of coronary angiography performed before and after acetylcholine injection, which led to a diagnosis of coronary-artery vasospasm.

A 47-year-old man who had lived in Laos and was taking prednisone for dermatomyositis presented with hemoptysis, rash, abdominal pain, and melena. He was found to have Strongyloides stercoralis hyperinfection syndrome.

A 52-year-old man presented to the emergency department with a 1-year history of headache and reduced visual acuity. Physical examination showed seesaw nystagmus; a video is available at NEJM.org.

A 53-year-old man presented with a dull, aching pain in his right nipple. Ultrasonographic findings confirmed a diagnosis of Mondor’s disease.

A 27-year-old man presented with a first seizure. Imaging revealed a very large arachnoid cyst.

A previously healthy 3-year-old boy presented with vomiting and fevers. Purpura developed on his body that evolved with the patient’s response to treatment.

Dysphagia developed in a 64-year-old man after posterior occipitocervical fusion for atlantoaxial subluxation. Videofluoroscopic studies that revealed nasopharyngeal regurgitation and delayed aspiration are available at NEJM.org.

A 62-year-old man presented with chest pain and was found to be hypertensive. A maneuver involving the use of a wooden stick, shown in a video, facilitated visualization of a prominent S4 gallop.

A 69-year-old man presented with neutropenia and anemia. Bone marrow aspirate revealed abundant Auer rods. Fluorescence in situ hybridization revealed a chromosome translocation confirming the diagnosis of acute promyelocytic leukemia.

A 71-year-old man presented for the evaluation of chronic kidney disease and was noted to have erythematous papules on his face and lesions over his toenails suggestive of tuberous sclerosis.

A 20-year-old man presented with a sore throat and a rash. A rapid test for streptococcal pharyngitis was positive, confirming a diagnosis of scarlet fever.

An 80-year-old man presented with a lesion on the left sole that had been growing in size during the past 2 years. An amelanotic melanoma was identified on biopsy.

A 30-year-old man was found to have tympanic-membrane perforation in both ears after a blast injury.

A 25-year-old man presented with neck pain after a high-speed motor vehicle collision. A radiograph and a computed tomographic scan showed fractures of the right and left pedicles of the C2 vertebra, sometimes called a hangman’s fracture.

A 55-year-old man presented with a 1-week history of severe headache. Imaging of the brain revealed a 4.5-cm mass in the right temporal lobe. Fluorescein was administered intravenously to facilitate tumor resection; a video shows uptake and accumulation of fluorescein.

An 89-year-old man presented with a 1-year history of a nonhealing groin rash that did not respond to antibiotics, antifungal agents, or glucocorticoids. A diagnosis of extramammary Paget’s disease was made by means of a skin biopsy.

A 30-year-old man presented with a 3-day history of a pedunculated lesion on his right lower eyelid. The clinical course and physical examination were suggestive of a pyogenic granuloma.

A 6-year-old girl presented with a single tooth, impaired hearing, vision loss, and short stature. Imaging helped in making the diagnosis.

A 72-year-old man who had been treated with long-term antibiotics presented with odynophagia. Endoscopy revealed linear, white lesions suggestive of candida esophagitis.

A 52-year-old man with a history of unexplained pancytopenia presented with cough and dyspnea. Findings on physical examination were suggestive of dyskeratosis congenita.

A 3-year-old boy presented with hematuria and abdominal pain. An abdominal radiograph showed stones in the kidneys, bladder, and left ureter. Mutational analysis confirmed primary hyperoxaluria type 1.

A 29-year-old woman presented 4 months after a vaginal delivery with a new mass protruding from her vaginal canal. A diagnosis of Gartner’s duct cyst was made histologically after resection of the mass.

A 42-year-old man who had been treated for severe coronary stenosis 4 years earlier presented with atypical chest pain. The imaging findings showed the potential value of medical therapy in treating stenosis.

A 46-year-old woman presented with pain and swelling in her right arm after a recent trip to the Ivory Coast. Oscillatory movements of larvae were noted over ulcerated areas near her right elbow.

A 33-year-old man presented with fatigue, skin lesions, and multiple, firm, nontender violaceous plaques in the oral cavity. He had a history of HIV infection and a low CD4 cell count.

A 46-year-old man with uncontrolled type 2 diabetes and alcoholic liver disease presented with painful swelling in his scrotum and perianal region; physical examination was notable for necrotic-appearing tissue in both areas.

An 86-year-old woman with a history of tuberculosis presented with symptomsof epigastric and chest pain. A dense opacity in the upper left lung wassuggestive of an oleothorax.

A woman presented to an ophthalmologist with allergic conjunctivitis. Slit-lamp examination revealed an incidental finding.

A 63-year-old man with multiple myeloma who had received extensive treatment for the condition presented with lesions on his arms and chest wall. Biopsy revealed plasmacytomas. Peripheral-blood smear revealed 25% plasma cells.

A 27-year-old woman presented with painful lesions on her left arm. A diagnosis was made with the use of a Tzanck smear.

A 65-year-old man with type 2 diabetes presented with weight loss and other symptoms that occurred after a rash had developed on his arms, genitals, buttocks, and legs. Imaging showed a pancreatic lesion.

A 67-year-old man who had previously had heart transplantation and had chronic kidney disease underwent coronary angiography. He had received pretreatment owing to a reported history of iodine allergy but reported neck swelling several hours later.

An 18-year-old woman had elevated aminotransferase levels and a workup negative for infectious and autoimmune disease. Liver biopsy revealed birefringent cholesteryl ester crystals consistent with lysosomal acid lipase deficiency.

A 40-year-old man presented with fever, weight loss, dyspnea, and cough. Physical examination revealed a tender, bulging anterior thoracic mass.

A 5-year-old boy presented with nausea, vomiting, and intermittent abdominal pain. Images showed giant cerebriform enlargement of rugal folds in the fundus and the body, which were suggestive of Ménétrier’s disease.

A 60-year-old man with clinically significant coexisting cardiac conditions presented with chest pain. Shortly after his initial admission, he suddenly collapsed. Scans showed air in his left ventricle.

A 50-year-old man presented with a 6-month history of pain, otorrhea, and progressive hearing loss in both ears. Polypoid masses were found in both external ear canals.

A 15-year-old boy presented with diminution of vision in both eyes. Slit-lamp examination revealed persistent pupillary membranes caused by the presence of remnants of the blood supply to the fetal lens.

A 39-year-old man presented with acute hemoptysis, chills, and a traumatized left finger. Despite treatment with antibiotics, a repeat imaging study performed 8 weeks later showed a persistent pulmonary infiltrate.

A 50-year-old man with alcohol dependence presented with acute symptoms of hematemesis. Imaging revealed extensive calcification of the pancreas.

A 50-year-old woman presented with asymptomatic, annular plaques on her forehead and the dorsum of her hands. Over time, the lesions gradually increased in number and slowly extended centrifugally.

A 48-year-old man presented with abdominal discomfort and lethargy. Examination revealed pallor, and laboratory studies showed mild anemia. Colonoscopy revealed a proglottid from a tapeworm, shown in a video, in the rectosigmoid colon.

A 72-year-old woman presented with skin changes on her left breast; 5 years earlier, she had undergone lumpectomy and radiation therapy for breast cancer. Examination revealed an area of skin that had an ecchymotic appearance, with no underlying mass or nodular tissue.

A 37-year-old woman taking adalimumab for ankylosing spondylitis presented with ulcerations with a hemorrhagic crust over her nose. Two waterborne organisms grew in biopsy samples obtained from the ulcers.

A 56-year-old man who had undergone gastric bypass 7 years earlier presented with midabdominal pain, nausea, and bilious emesis. Swirling of the bowel and mesenteric vessels was noted on CT.

A 37-year-old man presented with genital lesions, weight loss, and back pain, preceded 2 months earlier by dysuria and urethral discharge that had resolved. Examination revealed erythematous, annular plaques on the glans penis, and meatal inflammation.

A 68-year-old woman presented with exertional dyspnea and chest pain. She had undergone CABG 5 years earlier. Vascular examination revealed palpable radial pulses on both sides of the body; right brachial angiography revealed a “string of beads” pattern.

A 30-year-old man presented after a recent fall that had resulted from a loss of balance while he was walking. On examination, his vital signs were normal, but a palpable posterior fullness with swelling was seen over his left shoulder.

A 90-year-old man presented with progressive edema in both legs and malaise and dizziness associated with hypoglycemia. On examination, a nontender epigastric mass was palpated. A chest radiograph showed a round, irregularopacity inside the gastric chamber.

A 19-month-old girl presented with abdominal pain. The initial examination was normal, but within 24 hours the umbilicus became protuberant and erythematous. The white-cell count was elevated. CT revealed a cystic mass extending from the umbilicus to the dome of the bladder.

A 23-year-old woman presented with headache, vomiting, syncope, weight gain, and leg pain. MRI of the head and thighs revealed diffuse hyperintense cystic lesions, and antibodies to cysticerci were detected in the serum and CSF.

A 33-year-old woman presented at 22 weeks of gestation with a large herniation of the amniotic sac, detected by routine ultrasonography. MRI revealed a 2.5-cm rupture of the left uterine wall and a large amniocele that contained fetal legs.

A 36-year-old man presented with fever and pain in both shoulders and knees, which had been preceded by a sore throat. His symptoms abated after administration of an NSAID. One week later, painless, nonpruritic, red annular macules appeared on the upper limbs and abdomen.

A 9-year-old girl presented with knee pain and inability to extend her leg after landing on her flexed right knee while jumping on a trampoline. Physical examination revealed superior displacement of the patella.

A previously healthy 60-year-old woman presented with fevers, chills, myalgias, headache, and two pruritic areas on her back. She had returned 3 days earlier from a 2-week trip to Botswana and Zimbabwe that had included canoeing and camping.

An 18-year-old woman presented with a concentric, scaly rash on her arms, trunk, and legs that involved approximately 70% of the body-surface area. Her brother had similar skin findings.

A 15-year-old boy who lived with his family on a farm presented to the ED with vomiting, diarrhea, and altered sensorium. During insertion of a feeding tube, diffuse tongue fasciculations, shown in a video, were noted.

A 68-year-old woman was admitted to the ICU with respiratory failure and hypotension. Her blood pressure was 70/50 mm Hg, and her heart rate was 125 beats per minute. Physical examination revealed skin mottling on the legs.

A 44-year-old man with quadriplegia presented with symptoms of urinary tract infection. Extremely large, intermittent waves of peristalsis, shown in a video, were noted. CT revealed massive dilation of the transverse, descending, and sigmoid colon.

An 81-year-old woman presented with vomiting. Chest radiography showed a large air–liquid shadow in the inferior retrocardiac position, suggesting a paraesophageal hernia. CT showed a large retrocardiac mass that was consistent with herniation of the stomach into the chest.

A 33-year-old man participating in a research study underwent MRI in a 7-tesla MRI scanner. On entering the scanner, he had a spinning sensation for 2 minutes. Nystagmus, recorded with infrared goggles and shown in a video, continued for the entire 90-minute scanning period.

A 34-year-old woman with a history of appendectomy presented to the ED with acute abdominal pain. An intrauterine pregnancy had been diagnosed by her gynecologist. Transvaginal ultrasonography revealed a 4-cm right adnexal mass and free fluid in the peritoneal cavity.

A 47-year-old man with HIV infection had shooting pains in his legs, progressive difficulty in walking, tinnitus, and incontinence. Examination showed Argyll Robertson pupils, which are nonreactive to bright light but constrict whenfocused on a near object. A video is available at NEJM.org.

A 65-year-old woman with atherosclerotic cardiovascular disease and renal failure was hospitalized for acuterespiratory failure and bilateral pleural effusions. To rule out empyema, thoracentesis was performed. Hemothorax developed shortly after the procedure.

A 68-year-old man presented with unilateral ptosis. Neurologic examination revealed ptosis of the left eye after asustained upward gaze. Myasthenia gravis was suspected, and an ice-pack test was performed with an instant cold pack over the left eye.

A 72-year-old woman with poorly controlled hyperlipidemia and diabetes presented to the ED with lowerabdominal pain. Examination revealed lower abdominal tenderness, and blood tests revealed leukocytosis andelevated C-reactive protein and glucose.

A 46-year-old woman was brought to the ED because of agitation. On arrival, she had a fever, tachycardia, andocular flutter, as well as rigidity in the legs and myoclonus in the arms. Videos are available at NEJM.org.

A 53-year-old woman with tropical spastic paraparesis reported several months of worsening weakness of the legs and feet. On examination, she had severe spasticity and weakness of both legs and feet, bilateral Babinski sign, and bilateral patellar clonus, shown in a video.

A 51-year-old man presented with fever and general malaise of 2 weeks’ duration. He had poorly controlleddiabetes mellitus at the time of presentation. Imaging studies revealed gas collection in the parenchyma andperinephric space of the left kidney.

A 3-year-old boy presented to the ED with pain in the right ear and swelling in the postauricular area. When gentle pressure was applied to the postauricular area (shown in a video), keratin debris and purulence were expressed into the osteocartilaginous junction of the ear canal.

A 28-year-old woman presented with an erythematous rash on the nose and nasal area that appeared after she had manipulated a painful vesicular lesion. Cloxacillin therapy had a slight benefit followed by a worsening induration that prompted treatment with IV antibiotics, which had no effect.

An 8-month-old child was brought to the clinic by his parents, who reported that he had had white opacities and“shaky” eyes since 4 months of age. On examination, the child had wandering eye movements with bilateralcentral, dense, white, nuclear congenital cataracts.

A 60-year-old man presented with abdominal pain and hypotension. He had recently had thrombosis of thesuperior mesenteric artery; CT showed jejunal dilatation and thinning of the bowel wall. Videos show mucosalgangrene, hemorrhage, and healing.

A 38-year-old woman who had undergone three low-segment cesarean sections was admitted in labor at 36 weeks of gestation. Ultrasonography suggested placenta accreta, with irregular vascular spaces and loss of retroplacental hypoechoic stripe. She underwent an emergency cesarean section.

A 21-year-old man presented with a 2-week history of itching in his left eye. He reported “seeing worms” in his eye. He underwent thorough irrigation of the conjunctival sac and lacrimal duct. A video shows removal of three worms.

A 68-year-old man presented with a mass on the left side of his neck. A biopsy was performed, andhistopathological examination revealed squamous-cell carcinoma that was positive for HPV and overexpressedp16, a tumor-suppressor gene product.

A 59-year-old woman with a smoking history of 60 pack-years presented with progressive shortness of breath and clubbing of her fingers. CT scan showed a large mass with cavitation in the left lower lobe of the lung.

After recently arriving in Switzerland seeking asylum, a 24-year-old man from Eritrea presented to the ED withrecurrent fevers. He reported having had fevers approximately every 2 months for the previous 3 years.

A 76-year-old man with diabetes and mediastinal lymphadenopathy presented with fever and fatigue. Pyuria wasseen on urinalysis. CT of the abdomen showed mild dilatation of the left renal pelvis and thickening of theipsilateral ureteral wall.

An 88-year-old man with a history of MI for which he had required quadruple coronary-artery bypass graftingpresented with mottled purple discoloration of the toes. One month earlier, he had undergone transapicaltranscatheter aortic-valve replacement.

A 64-year-old man presented with widespread, erythematous-to-violaceous papules that were distributedsymmetrically on his trunk, arms, and legs. Skin biopsy revealed palisading granulomatous inflammation thatsurrounded degenerating collagen within the dermis.

A 13-year-old girl presented with a slowly enlarging, painful swelling of the scalp. She had received several courses of empirical oral antibiotics, without improvement. On examination, there was an erythematous, mildly tender, boggy swelling overlying her occiput.

A 65-year-old man was admitted for adjuvant radiotherapy after a previous tumor mass reduction and stabilizingspinal surgery for a synovial sarcoma. Ballooning of the left paravertebral soft tissues, which increased when theValsalva maneuver was performed, is shown in a video.

A 42-year-old man with diabetes presented to the ED with severe dysuria and incontinence. Laboratory studies were notable for pyuria, leukocytosis, elevated C-reactive protein, and hyperglycemia. Radiography showed an atypical focus of gas accumulation behind the right pubic ramus.

A human sneeze can eject droplets of fluid and potentially infectious organisms. The image sequence captures, inincrements of 20 msec, the emission of a sneeze cloud produced by a healthy person. Two videos show the samesneeze at normal speed and at a much slower speed.

A 79-year-old woman presented with gradual neurologic decline involving confusion, memory loss, imbalance, and incontinence. On examination, she was oriented only to self and had mild nonfluent aphasia. CT revealed a large left frontotemporal mass with areas of calcification.

A previously healthy 36-year-old Japanese woman presented with blood pressure that was difficult to control after an emergency cesarean section. CT revealed a disrupted abdominal aorta, severe stenosis of the renal arteries, and development of numerous collateral arteries.

A previously healthy 36-year-old woman presented with a 2-day history of severe chest pain and epigastric painassociated with nausea and vomiting. The patient reported that she had consumed uncooked salmon approximately 2 hours before the chest pain developed.

A 57-year-old man presented to the ED with peripheral edema. Physical findings were consistent with atrial fibrillation, tricuspid regurgitation, and heart failure on the right side. A radiograph of the chest showed a high cardiothoracic ratio and a very large right atrium.

A 62-year-old man with a history of hemodialysis and continuous ambulatory peritoneal dialysis presented withabdominal pain and refractory ileus. Imaging revealed calcification of the wall of the abdominal aorta, with near-total occlusion and stenosis of the superior mesenteric artery.

After collapsing in Munich, Germany, a 16-year-old male Somalian refugee was brought to a local hospital with severe headache and abdominal pain. His vital signs were notable for a temperature of 41°C, a heart rate of 105 bpm, and blood pressure of 95/50 mm Hg.

A 3-year-old girl presented to the ED on day 1 of a mild pruritic urticarial rash. The parents described a viral respiratory illness that had occurred a week earlier. Fever developed on day 2, along with a generalized polycyclic annular rash with wheals and ecchymotic centers.

A 46-year-old otherwise healthy man presented with a 1-year history of occasional dysphagia to solid foods that was not accompanied by weight loss. A barium-swallow examination revealed posterior oblique indentation of theproximal esophagus.

A 70-year-old man presented with a 2-day history of facial edema, rash along the left lower jaw, and plaque thatcovered two thirds of the left half of his tongue. He had had pain, otalgia, and glossodynia 3 days before theoutbreak of the rash.

An 18-year-old woman presented with recurrent episodes of diarrhea associated with epigastric discomfort and bloating. Examination of the stool revealed trophozoites of the species Giardia lamblia. Gastroduodenoscopy revealed multiple nodules in the duodenum.

A 56-year-old man was referred to a dermatologist for assessment of the progression of his thyroid dermopathy. Three years earlier, he had received a diagnosis of Graves’ disease with thyroid-associated ophthalmopathy and dermopathy.

A 71-year-old man with a history of gout and renal transplantation presented with a new blister overlying the second interphalangeal joint just distal to a preexisting tophus on his hand. Examination of the fluid showed sheets of negatively birefringent crystals.

A 67-year-old woman with malabsorption and malnourishment was referred for possible intestinal transplantation. CT showed small-bowel dilatation along with a whirl sign and numerous collateral veins, suggestive of a midgut volvulus, shown in a video.

An 87-year-old man presented with a stye on his left upper eyelid. Despite conservative interventions, the stye had persisted and the skin had become noticeably darker over several weeks. His risk factors included a history of prolonged sun exposure while working as a lifeguard.

A 48-year-old woman scheduled to receive a laparoscopic cholecystectomy underwent a preoperative evaluation. A laparoscopic exploration, shown in a video, revealed a smooth liver with normal consistency and morphology but with a grossly black appearance.

A 49-year-old man with diabetes was found to have blurred vision after admission to the hospital for investigationof elevated creatinine, liver enzymes, and bilirubin. He had been receiving treatment for bacteremia caused byKlebsiella pneumoniae associated with renal cortical abscesses.

A 36-year-old man who had AIDS with Kaposi’s sarcoma was referred for evaluation of extensive, painless oralpapillomatous lesions. His history included sex with men, and his partner had a history of anogenital warts. Thepatient was receiving highly active antiretroviral therapy.

A 57-year-old man presented with hematuria. Intravenous urography was performed after the administration ofiodinated contrast material. Several hours later, generalized pustular eruptions developed, with multiple coalescing vesicles and pus-filled bullae.

A 73-year-old woman presented with a persistent ulcer and white patch on the right margin of the tongue. Intraoral examination revealed a superficial ulcer with a homogeneous base, an indurated upper border, and an adjacent speckled red and white patch at the lower border.

An 86-year-old man in Minnesota presented with fever, dyspnea, and new-onset confusion. His history was notable for a febrile illness with night sweats and a weight loss of 23 kg (50 lb) that had occurred while he was in his late 20s, working in an abattoir slaughtering pigs.

A 48-year-old man with a history of end-stage renal disease who had undergone parathyroidectomy owing to tertiary hyperparathyroidism 1 month earlier presented to the ED with weakness and diffuse muscle aches after missing a hemodialysis session.

A 76-year-old man with a 1-week history of continuous chest pain presented to the ED with rapidly progressivedyspnea on exertion. Transthoracic echocardiography revealed a large, sharply demarcated interventricular septal defect with a turbulent left-to-right transseptal flow, shown in videos.

This man with febrile cerebral palsy presented with acute respiratory distress.

This 35-year-old man presented with sickle cell crisis and headaches.

An 83-year-old man was evaluated for frequent palpitations. During an episode, examination of the neck revealed rapid and regular pulsations with bulging of the internal jugular veins, shown in a video. A 12-lead electrocardiogram showed a regular, narrow-complex tachycardia.

A 58-year-old man with cryptogenic cirrhosis was admitted to the ICU with confusion after a fall. He had been taking metronidazole for C. difficile infection. MRI of the brain showed a fluid-attenuated inversion recovery (FLAIR) signal in the dentate nuclei of the cerebellum.

A healthy 18-year-old man was in a motor vehicle accident and sustained a head injury that resulted in intracranial bleeding at multiple sites, fractures of facial bones, and immediate traumatic mydriasis and ptosis in the left eye.

A 57-year-old man with a history of pain in the right knee presented with warmth and swelling in the right thigh. Examination revealed an asymmetric increase in right thigh volume. Radiography showed bony enlargement and cortical thickening.

A 27-year-old woman presented with a 2-year history of acanthosis nigricans, hirsutism, and amenorrhea.Laboratory tests revealed elevated levels of insulin and testosterone, the presence of thyroperoxidase antibodies, and an antinuclear antibody titer of 1:64 (normal titer, <1:32).

A 52-year-old woman and a 43-year-old man presented with erythematous and tender abdominal lesions. Bothpatients had previously been healthy, without a history of cancer or immunodeficiency.