Ultrastructure of human cutaneous candidosis.

Human skin biopsies were taken from patients with candidosis of the groin, axillary and submammary areas. The majority of the fungal cells were situated inside epithelial cells. The fungi invaded the entire stratum corneum. They were often found in parakeratotic epithelial cells. They could not be detected in noncornified cells of the malpighian layer. Mycelial forms predominated by far. They apparently invade the epidermis actively. Blastospores were found less often and they mostly were situated between or in superficial cells of the horny layer. Pseudomycelia and germ tubes were rarely observed. Remarkable was the frequent finding of lomasomas in Candida albicans cells in vivo, whereas these structures were rarely demonstrable in vitro. They probably represent structures that occur in damaged fungal cells as a result of defense mechanisms of the host. The fungal elements inside the epithelial cells were often surrounded by electron-transparent areas. These areas possibly resulted from keratolytic activities of the fungus. Characteristic manifestations of candidosis of the human skin were parakeratosis, spongiosis, and intracorneal and subcorneal micro-abscesses. However, fungal elements failed to occur in the center of these abscesses, possibly because the process of phagocytosis, killing, and lysis of the fungi had been completed.