Multicystic Mesothelioma

**Semantic type:** Neoplastic Process

**Definition:** A mesothelial neoplasm that arises from the peritoneum and rarely the pleura. It is characterized by the presence of multiple cysts lined by flattened or cuboidal mesothelial cells. There is no evidence of significant cytologic atypia or increased mitotic activity. It may reoccur. Rare cases of transformation to malignant mesothelioma have been reported.

**Synonyms:** - Cystic Mesothelioma - Intermediate Mesothelioma - Multicystic mesothelioma, benign