[Penile leiomyosarcoma. Ultrastructural study (author's transl)].

A case of leiomyosarcoma of the penis in a farmer aged 70 is described. The patient was treated by excision/biopsy, and six months later three little tumors recurred on the glans and prepuce. A wide local excision and direct suture was carried out. No troubles happened in the next eight months. The ultrastructural study confirmed the histogenesis showing: polymorphic cells, as well as clear and dark ones, reduction of intracytoplasmic myofilaments, anisocytosis and poikilokaryosis and wide infoldings of the nuclear membrane; very vascularized areas with confluent vesicles on the endothelial cells; and intersticial haemorrhages. This tumor is included among the superficial leiomyosarcomas of "low malignancy" of McKenzie Pratt et Ross, for which simple excision that avoid mutilations is suitable. Differential histologic diagnosis includes epithelioid sarcoma of Enzinger. Leiomyosarcoma of the penis is a very rare malinant tumor. Only 15 cases have been described in the literature. A further case is reported and the previous cases are reviewed.