A cardiac vascular hamartoma in a calf: ultrasonographic and pathologic images.

A right atrial mass was observed by ultrasound in a 3-month-old red Holstein calf. Differential diagnoses included endocarditis or tumor. Due to the poor prognosis, the calf was euthanized. On gross examination, there was a marked dilation of the right atrium. A round, poorly delineated, 2 cm mass was visualized in the right atrium. Microscopic findings were consistent with a vascular hamartoma.