Unexplained right hilar mass.

A right hilar mass was found on a computed tomographic (CT) scan in a 40-year-old man who presented with fever, sore throat, and general malaise. Initial testing ruled out various bacterial and viral infections and carcinoma. The patient's condition continued to deteriorate, and the mass as seen on repeat CT scan increased in size. Surgical biopsy of sections of the right lower lobe confirmed the diagnosis of histoplasmosis. Most histoplasmosis infections are asymptomatic, and even those that are not are usually self-limited and require only observation. When treatment is required, ketoconazole (Nizoral) now provides a less toxic alternative to amphotericin B (Fungizone).