Abstract
A 63-year-old woman was noted to have an asymptomatic cystic liver tumor on follow-up abdominal ultrasonography due to being positive for hepatitis B virus antigen. Computed tomography and magnetic resonance imaging revealed a cystic tumor 5cm in diameter with an internal tuberculum in the left hemiliver. The serum levels of all tumor markers were within normal ranges. Aspiration biopsy was not undertaken, to avoid dissemination of tumor cells in the abdomen, and a left hemihepatectomy was performed. In the resected specimen, an encapsulated cystic mass, with mucinous fluid and a white tuberculum in a part of the cystic wall, was found. Histologically, the inner layer of the cyst wall was lined with a single layer of columnar epithelium with partial papillary proliferation and slightly differentiated cells. The intermediate layer was composed of dense mesenchymal stroma, with estrogen and progesterone receptors identified by immunohistological examination, but was free of malignant components. From these findings, the tumor was diagnosed as hepatobiliary cystadenoma with ovarian-like stroma. Since diagnosis of a cystic liver tumor is difficult and hepatic cystadenoma is a rare neoplasm with possible malignant formation, complete tumor resection is essential.
