INTRACARDIAC THYROID-TUMOR IN A DOG - DIAGNOSIS AND SURGICAL REMOVAL

A 13-year-old, male, mixed-breed dog was presented for syncope precipi tated by stress or exertion. A grade 416 systolic murmur was ausculted low at the left heartbase. Echocardiographic evaluation revealed a so f tissue density mass within the right ventricular outflow tract. The mass appeared to be attached to the interventricular septum just below the pulmonic valve, obstructing the pulmonary valve orifice during sy stole. Paroxysms of ventricular tachycardia also were observed. Surgic al removal of the mass was accomplished via right ventriculotomy using hypothermia and venous inflow occlusion. Histologically, the mass was classified as an ectopic thyroid tumor. Two years after initial prese ntation the dog is well, with no echocardiographic evidence of tumor r ecurrence.