Two cases of primary hepatic neoplasia in young horses: Diagnostic challenges and clinical implications

Primary hepatic neoplasms are rare in horses and often have a poor prognosis due to non-specific clinical signs and delayed diagnosis. This report describes two cases of primary hepatic neoplasia in young horses. The first case was a yearling Hanoverian filly presenting with non-specific clinical signs, including poor weight gain and inappetence, ultimately diagnosed with hepatoblastoma based on ultrasonographic findings and histopathological examination. The second case was a three-year-old Polish Sport Horse stallion that died suddenly, with post-mortem examination revealing advanced cholangiocarcinoma, a malignant bile duct neoplasm. These cases highlighted the diagnostic challenges of hepatic neoplasms in horses due to non-specific early clinical signs. Hepatic neoplasms should be considered in the differential diagnosis in horses with unexplained weight loss and abnormal hepatic function, regardless of age.