Case of hepatocellular carcinoma in horse-report

Hepatocellular carcinoma (HCC) in horses is an uncommon hepatic neoplasm often presenting with vague clinical signs and diagnosed postmortem. This case report describes the clinical presentation, pathological findings and histopathological confirmation of hepatocellular carcinoma with concurrent pericardial haemorrhage in an adult horse. The animal exhibited nonspecific symptoms including lethargy, anorexia and respiratory distress prior to death. Clinical deterioration was rapid and the horse succumbed despite supportive treatment. A complete postmortem examination was performed revealing a markedly enlarged and nodular liver with pale to tan patches on surface, unclotted blood within the pericardial sac and heavy edematous lungs with frothy exudate. Microscopic examination of hepatic tissue revealed neoplastic hepatocytes arranged in trabecular and pseudoglandular patterns with marked cellular atypia and areas of necrosis consistent with hepatocellular carcinoma. The pericardium showed extensive haemorrhage and fibrin deposition while pulmonary sections exhibited alveolar congestion and emphysema. The histopathological findings confirmed a diagnosis of hepatocellular carcinoma with associated pericardial haemorrhage. This report highlights a rare multisystemic manifestation of hepatic neoplasia in equines and underscores the importance of thorough postmortem and histopathological investigations in diagnosing complex systemic conditions.