Localized malignant peritoneal mesothelioma arising in the mesentery of the ascending colon

Localized peritoneal tumors with mixed populations of tumor cells composed of epithelioid and sarcomatoid neoplastic cells are considered as malignant mesotheliomas, GISTs, or synovial sarcomas by differential diagnosis. [...]immunohistochemistry is important to diagnose malignant mesotheliomas. For accurate diagnosis of malignant mesothelioma, a combination of at least two or more positive mesothelial markers would be helpful.4 MPMA are easily revealed by diffuse or plaque-like peritoneal thickening, but localized malignant mesotheliomas are difficult to diagnose because their origins are unclear and they share histologic characteristics with other mesenchymal tumors such as GISTs and synovial sarcomas. [...]when a localized peritoneal mass is encountered and its histological origin is suspected to be the mesothelium, localized malignant mesothelioma should be considered in the differential diagnosis.