Cystic mesothelioma of peritoneum: occurrence in a man. We report a case of cystic mesothelioma of the peritoneum in a 54-year-old man in whom cystic masses were removed twice by surgery at an interval of 2 years. The patient died of cardiac arrest shortly after the second operation for a concurrent unresectable colonic cancer. The pathogenesis of the disease is uncertain, but we consider it neoplastic of low grade malignancy. 