The differential diagnosis of primary peritoneal papillary tumors.

Primary tumors of the peritoneum are rare. Histological differentiation between papillary mesotheliomas, primary ovarian tumors, borderline tumors of the ovary with peritoneal deposits and primary peritoneal carcinoma may be difficult. The expression of vimentin, keratin, pankeratin, CEA, CA125, CA19-9, S100, B72.3 and BerEP4 was therefore investigated in twelve women with primary malignant peritoneal tumors, twelve women with pleural mesothelioma, eight women with serous ovarian carcinoma and four men with peritoneal mesothelioma. The marker pattern we used was no help in differentiating between metastatic ovarian carcinoma and primary peritoneal carcinomatosis. A combination of the markers S100, B72.3 and BerEP4 helped the distinction between mesotheliomas and the other malignancies. If two or all three markers are detectable, primary peritoneal carcinomatosis or metastatic ovarian carcinoma is the possible diagnosis. If none of the three markers are found, a diagnosis of mesothelioma is highly probable.