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

backgroundOvarian 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 coffee-bean-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.

conclusionTo 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.