Left ventricular cardiac myxoma and sudden death in a dog

Background: Myxoma is a very rare benign cardiac tumor in dogs. This is the first description of a cardiac myxoma
originating from the left ventricular outflow tract, presumably causing sudden death.

Case presentation: A previously healthy 12-year-old male West Highland white terrier was found dead during its
1-week stay in a kennel. The dog was known to have a cardiac murmur. On necropsy, a pedunculated neoplasia
was found attached to the interventricular aspect of the left ventricular outflow tract, resulting in almost complete
obstruction of the aorta. As this was the only abnormality identified, the tumor was considered as the cause of sudden
death. Histopathologic findings were compatible with a myxoma.

Conclusions: Benign intraluminal tumors of the heart are very rare in dogs, but may have fatal consequences. Echocardiography
could have revealed the cause of the cardiac murmur of this previously asymptomatic dog. Surgical
removal could have been possible, as the tumor was pedunculated.