[Multicystic mesothelioma of the peritoneum].

Benign multicystic mesothelioma (MCM) of the peritoneum is a rare lesion that occurs predominantly in middle aged women with previous history of pelvic surgery. We report a case of MCM of the peritoneum in a 25-year-old man in whom cystic masses were twice surgically removed in an interval of 1.5 year. Ultrasonography and computer assisted tomography of the abdomen revealed a multicystic abdominal and pelvic mass. At first laparotomy, a multiple, thin-walled cysts ranging 0.5-7 cm in diameter were found involving the abdominal and pelvic peritoneum. After removal of all visible cysts we made histopathological diagnosis of the multilocular cavernous lymphangioma, without immunohistochemical examinations. The recurrent tumor was clinically and pathologically identical, but the final diagnosis, established upon immunohistochemical staining, was MCM: the tumor cells were strongly positive for cytokeratin, weakly positive for vimentin, and negative for Factor VIII. Management of the MCM surgical excision, unfortunately not always curative, since there is a high recurrence rate.