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

Abstract 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.