Histopathological and Immunohistochemical Insights into Ovarian Tumours in Sheep: A Comprehensive Study

Ovarian tumours, though common in domestic animals, have been sparsely studied in sheep due to their early slaughter upon infertility. This study investigated 212 ovaries collected from 106 sheep to identify and characterize neoplasms. Histopathological and immunohistochemical analyses revealed one sex cord-stromal neoplasm (granulosa cell tumor), three epithelial neoplasms (adenoma, adenocarcinoma, clear cell carcinoma) and four mesenchymal neoplasms (hemangiosarcoma, fibroma, angioleiomyoma, hemangiopericytoma). Granulosa cell tumours were the most prevalent and exhibited distinct histological patterns, including Call-Exner bodies and multifocal coalesced patterns. Adenocarcinoma and cystadenoma presented characteristic growth patterns, while mesenchymal neoplasms exhibited unique histological and immunohistochemical features, such as VEGF positivity in hemangiosarcoma and SMA positivity in angioleiomyoma. These findings align with previous reports in other species, emphasizing the importance of immunohistochemistry in tumor classification and contributing valuable insights into the occurrence and pathology of ovarian tumors in sheep.