Problems in the Pathological Diagnosis and Intraoperative Rapid Diagnosis of Mucinous Tumor of the Ovary

The pathological (histological and cytological) diagnosis of mucinous ovarian tumors presents the following problems: 1) conflicting definitions of borderline tumors, intraepithelial carcinoma and microinvasive carcinoma, 2) mural nodules within mucinous cystic tumors, 3) differential diagnosis in primary vs. metastatic mucinous tumors, and 4) difficulties in the intraoperative rapid diagnosis of mucinous ovarian tumors. Mucinous adenocarcinomas may include benign and/or borderline tumor components in other areas of the tumor. Therefore for pathological diagnosis, the sampling of these tumors must include up to one histological section per 1 to 2cm of tumor diameter as well as sampling of any suspicious lesions (multilocular and solid areas including mural nodules). The most important differential diagnosis for mucinous ovarian carcinoma is metastatic mucinous carcinoma. Histological findings from metastatic mucinous carcinoma from the appendix, large intestine, stomach, pancreas, and cervix are similar. In general, immunohistological staining, such as cytokeratin 7 (CK7) and CK20, is necessary to determine the origin of the cancer. False-negative diagnoses from frozen sections can occur due to limited sampling, as only a few frozen sections (1 or 2 in our hospital) can be taken from each tumor. Cytological specimens (scrape or imprint smears) which are sampled from any suspicious lesions or from almost all cut surfaces of the tumors can facilitate intraoperative rapid diagnosis of mucinous ovarian tumor