Is PAX2 a reliable marker in differentiating diffuse malignant mesotheliomas of peritoneum from serous carcinomas of müllerian origin?

Diffuse peritoneal malignant mesotheliomas (DPMM) are often disseminated in the peritoneal cavity as multiple nodules including localized masses in the ovaries that are clinically and histologically similar to serous adenocarcinomas of müllerian origin. It is imperative to differentiate these tumors given their diverse responses to chemotherapy and/or radiotherapy. PAX2 gene was recently demonstrated in benign epithelial cells of the female genital tract and in serous carcinomas (SC) of müllerian origin. The aim of our study was to determine if PAX2 can reliably be used in differentiating DPMM from SC. A total of 59 cases to include 25 cases of DPMM and 34 cases of SC were retrieved. All cases were stained with PAX2, Wilm tumor gene 1, calretinin and the results were compared. Our results demonstrate that PAX2 can be used reliably as a Müllerian marker in formulating an efficient panel to differentiate DPMM and SC.