Rare form of extraovarian primary peritoneal papillary serous carcinoma with solitary cystic lesion mimicking a liver tumor; report of a case.

Extraovarian primary peritoneal serous papillary carcinoma (EOPPC) has a similar clinical presentation to that of ovarian cancer in advanced stages, such as peritoneal dissemination and a large amount of ascites, while EOPPC with a solitary tumor is very rare. We report here a 47-year-old Japanese woman with solitary form of EOPPC mimicking a liver tumor. Ovaries of both sides had no malignant lesion, which was histologically confirmed. Histological examination revealed that the tumor was located at the right diaphragm and partially invaded into the liver, and papillary or ductal proliferation of the tumor cells with an occasional appearance of psammoma bodies was detected. Immunohistologically, the tumor cells were positive for CA 125 and Ber-EP4 and negative for D2-40 or calretinin, ruling out the possibility of mesothelioma, and the diagnosis of the tumor was EOPPC. After the operation, the patient received chemotherapy with carboplatin and paclitaxel, but died 10 months later due the progression of recurrence. The present case is very rare form of EOPPC without any ascites or peritoneal dissemination.