Cardiac myxoma in a dog

Abstract

Cardiac tumours occur very rarely in domesticated animals and humans. The most common cardiac tumours in dogs are hemangiosarcoma and chemodectoma. Myxoma, on the other hand, occurs extremely rarely. In this report, we present a case of an 11-year-old, spayed, mixed-breed dog with a myxoma arising from the tricuspid valve. The dog presented with syncope, tachypnea, tachycardia, exercise intolerance and progressive ascites. Two-dimensional echocardiography showed a polypoid intracavitary mass in the right heart. At necropsy, a polypoid, red mass was observed arising from the tricuspid valve. Histologically, the mass was composed of spindle-shaped and stellate cells with small hyperchromatic nuclei surrounded with myxoid matrix. After performing immunohistochemistry, the neoplastic cells were found to be strongly positive for vimentin. Based on gross, microscopic, and immunohistochemical staining features, the neoplasm was diagnosed as a cardiac myxoma.