Clinical Pearls & Morning Reports
Published July 5, 2023
Sarcoidosis can be diagnosed with an appropriate clinical presentation, evidence of nonnecrotizing granulomas on tissue biopsy, and ruling out of other causes of granulomatous disease. Sarcoidosis typically involves the lungs (in 95% of patients in a large series), skin (in 24%), lymph nodes (in 15%), eyes (in 12%), and liver (in 12%), but it also can involve other organs. Read the NEJM Clinical Problem-Solving Article here.
Q: What are some of the entities that can mimic the histology of sarcoidosis?
A: Effacement of lymph-node architecture by granulomas with a nonnecrotizing core is characteristic of, but not specific for, sarcoidosis. Fungal and mycobacterial infections should be ruled out with microbiologic cultures and stains, although classically both tuberculosis and fungal infection would appear histologically as necrotizing (caseating) granulomas. Sarcoid-like granulomatous reactions may also be seen in association with Hodgkin’s lymphoma, non-Hodgkin’s lymphomas, seminoma in men, and a variety of carcinomas.
Q: Describe characteristic dermatologic manifestations of sarcoidosis.
A: Dermatologic manifestations include erythema nodosum (tender, subcutaneous nodules due to panniculitis, often overlying the shins), waxy facial papules, and lupus pernio (chronic, violaceous plaques, often on the nose and cheeks). Skin lesions at tattoo sites are characteristic of sarcoidosis; they may occur in response to specific pigments and can develop long after a tattoo is placed. Lesions also may occur at sites of trauma (“scar sarcoidosis”).
A: After the diagnosis of sarcoidosis, evaluation should be pursued for other sites of involvement, including the heart and eyes. Although clinical manifestations of cardiac involvement are rare, a study involving autopsies of persons with sarcoidosis showed evidence of granulomas (often microscopic) in approximately a quarter of cases. Cardiac involvement is a major cause of death, related to arrhythmias. Patients should undergo electrocardiographic screening and be evaluated for symptoms such as palpitations, lightheadedness, and syncope. If there is concern about cardiac involvement, Holter monitoring, echocardiography, and possibly additional imaging by cardiac magnetic resonance imaging or positron emission tomography should be pursued. Because ocular involvement can be asymptomatic, all patients should undergo ophthalmologic evaluation. Imaging often reveals asymptomatic involvement of other tissues, including bone and muscle. Bony involvement can involve the axial skeleton, hands, and feet, as well as large-joint and small-joint arthritis.
A: Treatment for sarcoidosis is not routinely needed but is indicated in persons with progressive symptoms or organ injury. Clinical trial data and consensus guidelines support the first-line use of glucocorticoids, usually prednisone at a dose of 20 to 40 mg daily, which is typically tapered after 3 to 6 months (or earlier if important adverse effects occur). If glucocorticoid treatment cannot be successfully tapered, immunosuppressive agents such as methotrexate, tumor necrosis factor inhibitors, or other medications (mycophenolate mofetil, leflunomide, or azathioprine) can be added.