Colonic Histoplasma capsulatum Infection Simulating a Polypoid Lesion: Reactivation of a Long-Dormant Disease in a Patient With Chronic Renal Failure.

A 73-year-old Japanese man undergoing hemodialysis for chronic renal failure, with a history of sigmoid colon low-grade adenoma, underwent follow-up colonoscopy. A 5 mm rectal polypoid lesion was identified and resected by endoscopic mucosal resection. Histopathological examination revealed granulomas and clusters of histiocytes containing intracytoplasmic yeast-like organisms. Polymerase chain reaction analysis of paraffin-embedded tissue identified the genome of Histoplasma capsulatum. The patient had visited Brazil 30 years earlier, where he was presumed to have acquired the infection without developing clinical disease. Following the onset of immunocompromised status associated with long-term hemodialysis, the previously latent H. capsulatum infection appeared to have reactivated.