Multiple persistent vitelline duct cysts in a dog.

Persistent vitelline duct remnants, with the exception of Meckel's diverticulum in pigs and horses, are rare in animals. During an ovariohysterectomy of an 8-month-old Labrador Retriever, multiple fibrous nodules with cystic centers were found attached to the ileal serosa and in a mesodiverticular band attached to the abdominal wall. Histologic and ultrastructural evaluation revealed that the cysts were composed of well-differentiated intestine with mucosa, submucosa, and muscularis layers surrounded by a thick layer of fibrous connective tissue. The morphology and arrangement of lesions were consistent with multiple persistent vitelline duct cysts, a distinct condition related to Meckel's diverticulum. This case in a dog represents a unique presentation of this congenital anomaly in domestic animals.