Metastatic Hepatobiliary Cystadenocarcinoma Mimicking a Gynecologic Malignancy

Abstract

Hepatobiliary cystadenocarcinoma is a rare malignancy associated with ovarian-like stroma and overtly malignant glands that has a favorable prognosis if completely resected, analogous to minimally invasive adenocarcinoma arising in mucinous cystic neoplasms of the pancreas. Ovarian mucinous neoplasms may have a similar histologic appearance and are known to occasionally contain mural nodules of anaplastic carcinoma. We report a case of hepatobiliary cystadenocarcinoma that subsequently presented as metastatic disease mimicking a primary gynecological malignancy. The 30-year-old patient had a history of a completely resected hepatobiliary cystadenocarcinoma 2 years prior to presentation, without adjuvant therapy. She presented to her gynecologist with pelvic pain and vaginal bleeding. Physical examination revealed diffuse nodularity along the anterior vaginal wall, and imaging showed a 5.8 × 4.1 cm pelvic mass with diffuse metastatic disease. Biopsies of the vaginal wall and an inguinal lymph node showed nests of pleomorphic cells with squamoid and glandular features concerning for metastatic ovarian carcinoma; however, immunohistochemistry was negative for PAX8 and ER, but positive for CDX2. Subsequent review of the patient's prior resection revealed a cystic mucinous neoplasm with mural nodules of adenosquamous and anaplastic carcinoma, the latter previously reported only rarely in hepatobiliary cystadenocarcinoma. This case highlights the histologic overlap between hepatobiliary and ovarian neoplasms, which may present a diagnostic challenge, particularly in the setting of incomplete history. In addition, the unusual presence of an anaplastic component in the patient's original tumor portends a worse prognosis; therefore, additional therapy should be considered in these patients.