Intrahepatic cholangiocarcinoma metastatic to the ovary: a report of 16 cases of an underemphasized form of secondary tumor in the ovary that may mimic primary neoplasia.

The potential for adenocarcinoma metastatic to the ovary to mimic primary mucinous neoplasms is a well-known issue to surgical pathologists, most of the recent literature emphasizing pancreatic and various other origins for the ovarian metastases. Although an origin in the gallbladder or extrahepatic bile ducts is acknowledged for some cases little information exists on tumors originating within the intrahepatic bile ducts. Sixteen cases of this type were retrieved from the surgical pathology files of the Chiang Mai University Hospital between January 1992 and December 2006. The patients ranged from 38 to 74 years (mean 52). Thirteen presented with nonspecific pelvic symptoms similar to primary ovarian neoplasms. The hepatic tumors were radiologically detected before the ovarian lesion in 2 cases. Hepatic and ovarian masses were simultaneously detected by preoperative radiologic studies or at exploratory laparotomy in 10 cases. In the remaining 4 cases, the hepatic lesions were detected postoperatively. There were a total of 26 metastatic ovarian lesions which included 22 clinically recognized ovarian masses (range 3 to 20 cm, mean 11.8 cm). Bilateral involvement was present in 10 cases (62%) and unilateral involvement in 6 (38%). The cut surfaces of the 22 grossly enlarged ovaries were predominantly solid in 5, solid-cystic in 10, and multicystic in 7. Microscopically, surface implants were observed in 80% of tumors, multinodular growth in 48%, and infiltrative stromal invasion (including microinvasionlike foci as it would be applied if the tumors were primary) in 86%. The neoplastic epithelium typically formed glands that ranged from small to large and cystically dilated, but small clusters of cells and individual cells were also seen. The epithelium ranged from tall, columnar, and mucinous in appearance to cuboidal or flattened and nonspecific. The tumors most closely mimicked primary mucinous neoplasms although a resemblance to other mullerian neoplasms was also seen. Foci often mimicked mucinous borderline tumors of typical type or with intraepithelial carcinoma and benign-appearing mucinous epithelium was seen in 62% of tumors. Immunohistochemical studies in 15 cases showed a positive reaction for cytokeratin 7 in all and for cytokeratin 20 in 5 cases. Intrahepatic cholangiocarcinoma should be included in the list of origins of possible ovarian metastatic tumors that mimic primary ovarian mucinous neoplasia, particularly in parts of the world where cholangiocarcinoma of the liver is relatively common.