A case report of disseminated blastomycosis presenting as a renal mass

Blastomycosis, caused by dimorphic fungi from the genus Blastomyces, is an endemic disease of the midwestern United States that typically presents as pulmonary disease mimicking community acquired pneumonia. Extrapulmonary blastomycosis occurs in up to 50% of cases and most commonly involves the skin. Genitourinary blastomycosis is a rare entity most often seen in disseminated systemic blastomycosis, and rarely as the presenting manifestation of blastomycosis. Here we describe a case report of a 78-year-old Midwestern man incidentally found to have a large kidney mass and multiple pulmonary nodules. Renal biopsy revealed multiple sites of granulomatous inflammation and budding yeast consistent with Blastomyces species. We present the patient’s clinical history, treatment regimen, and clinical course.