[Buccal histoplasmosis. Apropos of a case with a difficult histopathologic diagnosis]

A 65-year-old man who had lived in several tropical countries, particularly in Brazil, is observed for an ulcerative lesion of the mouth that appeared two months ago. The biopsy reveals polymorphic granuloma with numerous giant cells. PAS and Gomori-Grocott stains show very numerous roundish structures of variable size (3 microns to 15 microns). There are multiple buds like in paracoccidioidomycosis but culture reveals Histoplasma capsulatum. These abnormal forms have been described in large necrotic zones and especially in endocarditis (intravascular proliferations). To our knowledge, it is the first description of these forms in primary infestation. This case shows the necessity to control histological diagnosis of mycosis. Culture and biological identification are absolutely necessary for specific diagnosis.