Right-sided heart failure in a dog with primary cardiac rhabdomyosarcoma

A seven-year-old, female German shepherd mixed-breed dog was presented with weakness, inappetence, and a distended abdomen. Right-sided heart failure with pleural, pericardial, and abdominal effusions; dyspnea; and tachycardia were identified. The radiographic and electrocardiographic examinations did not allow a conclusive diagnosis. Echocardiographic findings included a mass in the wall of both the right atrium and right ventricle, partially occupying the right heart cavities. A diagnosis of cardiac tumor was made, and the owner elected euthanasia. The necropsy confirmed a tumor mass located in the right atrium and right ventricle. A definitive diagnosis of primary cardiac rhabdomyosarcoma was based on histopathological and immunohistochemical analyses.