Histopathology of presumed ocular histoplasmosis.

A 46-year-old man with the clinical picture of presumed ocular histoplasmosis had its right eye removed because of an associated choroidal malignant melanoma. Histopathologically, the choroidal foci disclosed the different stages of inflammatory evolution; from granulomatous foci with caseation, macrophages, and giant cells, to nongranulomatous lesions composed of lymphocytes, and finally to the healing stage of fibrohyaline scarred lesions. The granulomatous lesions contained PAS-positive and Grocott-positive bodies and dead Histoplasma organisms. Electron microscopy demonstrated that the dead fungi did not disappear from the tissue and were detected nine years after the initial infection.