Ovarian granulosa cell tumor in bovine fetus

Ovarian granulosa cell tumor (GCT) is a common type of sex cord neoplasm in cattle. This paper reports a rare case of GCT identified in a bovine abortion. A necropsy was performed on an 8-month-old bovine fetus, revealing an enlarged right ovary measuring 5.5 cm. The cut surface displayed reddish cystic areas with mucinous content, interspersed with whitish to blackish regions. The histopathological evaluation identified a benign epithelial neoplastic proliferation with an acinar arrangement supported by fibrocollagenous stroma. Immunohistochemistry was performed using antibodies against cytokeratin AE1/AE3, vimentin, protein S-100, chromogranin A, inhibin, and somatostatin. The tumor stained positive for cytokeratin AE1/AE3 and vimentin, while protein S-100, inhibin, chromogranin A, and somatostatin were non-reactive. Polymerase chain reaction (PCR) tests for Toxoplasma gondii, Neospora caninum, and bovine viral diarrhea virus yielded negative results. This report provides a detailed anatomical, histopathological, and immunohistochemical characterization of a congenital GCT in a bovine fetus.