A 54-year-old farmer presents to his physician with chronic cough. Chest x-ray demonstrates a mass lesion with hilar lymphadenopathy. Biopsy of the mass demonstrates multiple, tiny yeast forms within macrophages. Which of the following is the most likely diagnosis? (AIPG 2012)
Histoplasma capsulatum primarily infects the reticulo-endothelial system. Microscopic examination of the biopsy of the lyph nodes shows yeast cells in macrophages.