Cardiac hematoma with pericardial effusion in a dog

A 12-year-old spayed female, Golden Retriever presented with dyspnea and lethargy of 3 months duration. Pericardial effusion and cardiac mass were identified on echocardiography. Pericardiectomy and mass resection were performed for treatment of pericardial effusion and histopathological analysis was conducted for the definitive diagnosis. The mass was diagnosed as hematoma with mainly erythrocyte, fibrin and many of neutrophils based on microscopic description. Severe purulent pericarditis thickened by inflammatory cells and reactive fibrous tissue were identified, but not diagnosed as neoplasm. This is the first case report in veterinary literature of a dog with pericardial effusion caused by cardiac hematoma.