Immunohistochemistry in the differential diagnosis in the second-look operation for ovarian carcinomas.

The second-look laparotomy is the procedure of choice to obtain peritoneal and nodal biopsies from patients who have received a full course of chemotherapy for an ovarian malignancy. If there is pathologic evidence of persistent tumor, chemotherapy is continued. In most cases, the histopathologic interpretation is straightforward in terms of positive or negative results. However, atypical mesothelial reactions or glandular inclusions, or both, in lymph nodes are potential and real difficulties in differential diagnosis. This study evaluated a panel of immunohistochemical markers, namely carcinoembryonic antigen (CEA), Leu M1, human milk fat globule protein, cytokeratin, epithelial membrane antigen, and LN2 antibody for their usefulness in differentiating benign epithelium and mesothelium from carcinoma. Only CEA and Leu M1 were specific and sensitive, respectively, for malignant tumors in this study.