[Histopathology and ultrastructure of chromomycosis caused by Cladosporium carrionii].

Light and electron microscopic study of chromomycosis caused by C. carrionii was undertaken. Biopsies from 10 patients were taken and processed by means of conventional histopathologic techniques of hematoxylin and eosine and by transmission electron microscopy. Granulomatous and suppurative components of the infection process were observed by the histological procedure, other cellular elements such as lymphocytes, plasma cells, eosinophils and Langerhans cells were present. The fungus was observed free or within phagocyticcells. Ultrastructural evidence revealed that it was surrounded by a wide multilayered and electron dense cell wall. Its cytoplasmic membrane presented invaginations and vacuoles containing the electron-dense material. We suggest the existence of a secretion-excretion process of a melanin-like dark pigment, which is accumulated on the cell wall of fungus, increasing the resistance of fungal cell to its destruction by phagocytic cell. It is necessary to determine the exact role of Langerhans cells in chromomycosis caused by C. carrionii.