Surgical resection of a left auricular aneurysm in a dog.

Aneurysmal dilation of the atrial appendage (auricle) is rare in humans and dogs. Congenital and acquired etiologies are hypothesized. Although right auricular aneurysm has been described in dogs, this is the first case report of an aneurysm of the left auricle of a dog with an intact pericardium.