Histoplasma Colitis: An Electron Microscopic Study

Abstract

Gastrointestinal histoplasmosis may be manifest as chronic diarrhea with polypoid transformation of small and large bowel mucosa. Sequential light and electron microscopic findings on rectal biopsies obtained before, during, and 1 year after a course of amphotericin are compared. The initial biopsy showed numerous viable-appearing budding intracellular fungi. At completion of amphotericin therapy, only degenerating and dead organisms were present. After a 1-year clinical remission, no organisms could be demonstrated with light microscopy, although electron microscopy revealed remnants of fungi cell wall still present within macrophages.