Ovarian Granulosa Cell Tumor Initially Presenting as a Giant Liver Mass Radiologically Mimicking Primary Cystic Cholangiocarcinoma

Abstract

Background: Ovarian granulosa cell tumor (GCT) is a rare type of malignant sex-cord stromal tumor, with adult and juvenile types. The ovarian GCT initially presented as a giant liver mass clinically mimicking primary cholangiocarcinoma is exceedingly rare. Case Report: We report such a case of a 66-year-old woman who presented with right upper quadrant pain. Abdominal magnetic resonance imaging (MRI) and a subsequently fused positron emission tomography/computed tomography (PET/CT) showed a solid and cystic mass with hypermetabolic activity concerning intrahepatic primary cystic cholangiocarcinoma. A fine-needle core biopsy of the liver mass showed coffeebean-shaped tumor cells. The tumor cells were positive for Forkhead Box L2 (FOXL2), inhibin, Wilms tumor protein 1 (WT-1), steroidogenic factor 1 (SF1), vimentin, estrogen receptor (ER), and smooth muscle actin (SMA). The histologic features and immunoprofile supported a metastatic sex-cord stromal tumor favoring granulosa cell tumor, adult type. Strata next-generation sequencing test was performed on the liver biopsy and FOXL2 c.402C>G (p.C134W) mutation was present, consistent with granulosa cell tumor. Conclusion: To the best of our knowledge, this is the first documented case of ovarian granulosa cell tumor with FOXL2 mutation initially presenting as a giant liver mass clinically mimicking primary cystic cholangiocarcinoma.