[A case of malignant lymphoma, an anemone cell tumor of the leg, arising from osteomyelitis].

An 80-year-old man, complaining of multiple fungating growth on his right leg, was hospitalized. A review of his previous history revealed that he had undergone three operations because of repeating osteomyelitis. A clinical examination showed that a tumor was localized on the right leg. Light microscopy revealed that tumor was composed of diffuse large round cell proliferations. Malignant lymphoma was suspected, but was difficult to distinguish in the undifferentiated carcinoma. Electron microscopically, extensive cytoplasmic processes resembling microvilli from the circumferential surface membrane were observed, but desmosomes, tonofilaments, secretory products or basal lamina were not seen. Immunohistochemically, IgG was demonstrated on the tumor cells. These findings led us to diagnoses an anemone cell tumor, originating from a malignant lymphoma and arising from osteomyelitis.