Acquired arteriovenous fistula secondary to castration in a dog.

A 6-year-old castrated male Basset Hound was examined because of a 1-year history of a pulsating mass in the right inguinal region. The pulsatile mass was diagnosed as an arteriovenous fistula by physical examination and angiography. Surgical exploration revealed that the right testicular artery and vein, the artery of the ductus deferens, and the cremasteric artery were involved in the fistula. The fistula was believed to have developed secondary to castration performed at 6 months of age. The mass and associated vessels were completely excised and signs of recurrence were not observed 13 months after surgery.