1994 Volume 47 Issue 7 Pages 499-501
In a 2 year and 8 month-old female Golden Retriever dog showing vomiting, decreased appetite and activity, muffled heart sound, inaudible lung sound and acumulation of chest fluid, a large mass occupying the right atrium was detected by radiography and echocardiography. At necropsy, a dark red and soft tumor mass 3.5×3.0×3.5cm in size was found on the tricuspid vulve. Histopathologically, the mass had no heart muscle fibers, and stellate or spindle shaped tumor cells showing no atypia and mitotic figures were scattered in the slightly acidophilic myxomatous matrix with hemorrhage and infiltration of inflammatory cells. It was histopathologically diagnosed as a myxoma in the right atrium.