Ultrastructural study of a cerebral toruloma.

Biopsy tissue from a human cerebral toruloma was studied ultrastructurally. Numerous yeasts were found within extracellular space and within macrophages or epithelioid cells and demonstrated a prominent mucopolysaccharide capsule. Extensive vacuolization of yeast-bearing macrophages was demonstrated. Coating material lined these vacuoles as well as the surface of these cells where numerous contacts with lymphocytes were observed. The macrophages further displayed prominent subplasmalemmal linear densities, structures common to epithelioid cells in granulomatous diseases as well as a variety of cells of presumed mesodermal origin.