Multicystic mesothelioma of the peritoneum

: A case of multicystic peritoneal mesothelioma in a young woman is reported. Tumor consisted of multiple cysts involving the pelvic peritoneum. The cells demonstrated positive staining for keratin peptides, and epithelial membrane antigen. No staining was demonstrable for endothelial markers. The findings are in accord with the proposed mesothelial origin of the neoplasm and can be of help in the differential diagnosis of the other multicystic neoplasm arising in the peritoneal cavity.