[Case of malignant mesothelioma presenting as a perineal and intrascrotal mass].

We report here a case of malignant mesothelioma presenting as a perineal and intrascrotal mass. A 42-year-old Japanese male presented with an enlarging mass in the perineum and intrascrotum. Although the initial clinical diagnosis was perineal abscess, angiography revealed a tumor in the perineum and intrascrotum. The tumor was resected, and the pathological examination revealed malignant mesothelioma. Two months after the operation, a hard irregular mass with severe hemorrhage was noticed in the perineum, and was resected. A few weeks after the second operation local recurrence and, inguinal and intrapelvic retroperitoneal lymphadenopathy were found. Radiotherapy to recurrent sites was not effective. The patient died six months after the initiation of therapy. To our knowledge, 24 cases of malignant mesothelioma in the perineum or intrascrotum were reported in Japan and this case was thought to be the 25th case in Japan.