Clinical Pearls & Morning Reports
Published August 9, 2023
Incidental findings on chest CT are common. A chief concern with any incidental nodule is the possibility of cancer. Read the NEJM Case Records of the Massachusetts General Hospital here.
Q: Do pulmonary nodules develop in patients with cryptococcosis?
A: Cryptococcosis occurs worldwide, but disseminated disease is rare in immunocompetent patients. The infection is asymptomatic in approximately one third of immunocompetent patients. Pulmonary nodules that develop with cryptococcosis can be solitary or multiple but are usually peripherally located; mediastinal lymphadenopathy can occur but is uncommon.
Q: Name some of the inflammatory diseases that can cause pulmonary nodules.
A: The list of inflammatory conditions that can cause pulmonary nodules is extensive. It includes, but is not limited to, sarcoidosis, aspiration, IgG4-related disease, rheumatoid arthritis, vasculitis (e.g., granulomatosis with polyangiitis), amyloidosis, inflammatory bowel disease, and common variable immunodeficiency.
A: Coccidioidomycosis can be caused by one of two distinct species: Coccidioides immitis, which is endemic in California, and C. posadasii, which is endemic in the southwestern United States and in Central and South America. The infection is asymptomatic in up to 60% of cases. Patients can present with self-limited pneumonia, but they frequently also have a solitary pulmonary nodule. As a result, the evaluation of lung nodules and lung cancer screening can be challenging in geographic regions where the disease is endemic.
A: Histoplasmosis is a fungal infection that is endemic in Central and South America. Histoplasma is found at high concentrations in bird and bat droppings, so persons with exposure to chicken coops or caves are at an increased risk for infection. Up to 90% of persons with exposure to the fungus have only mild or no symptoms. Histoplasmosis is associated with a range of pulmonary manifestations. Approximately 10% of patients present with acute pulmonary histoplasmosis, which includes fever, cough, and dyspnea. Of these patients, 5% also have skin or joint manifestations, such as arthralgias, arthritis, erythema nodosum, or erythema multiforme. With acute pulmonary histoplasmosis, diffuse patchy opacities are seen on imaging; mediastinal and hilar lymphadenopathy are very common. Histoplasmosis is a very common cause of pulmonary nodules. In one case series focusing on infections that mimic lung cancer, histoplasmosis was the most common fungal cause. Other pulmonary manifestations of histoplasmosis include chronic cavitary pulmonary histoplasmosis, which is seen mostly in older patients with chronic obstructive pulmonary disease, as well as mediastinal granulomas and mediastinal fibrosis.