Polyorchidism in a cat.

A 9-mo-old, male domestic shorthair cat was presented for castration because of mounting behavior observed by the owner. On physical examination, the cat was bilaterally cryptorchid, but had penile spines. Abdominal exploration through a midline laparotomy revealed 2 pairs of masses. All 4 masses had gross features of testes, and ranged from 7 × 5 × 5 mm to 12 × 6 × 7 mm, with associated epididymal tissue. Histologically, each mass contained seminiferous tubules consistent with testicular tissue, and epididymal tubules, confirming a diagnosis of polyorchidism; deferent ducts were not found. There was no evidence of neoplastic, infectious, or inflammatory disease. Mounting behavior ceased 4 wk post-surgery. Histologic confirmation of more than 2 testes is needed to establish a diagnosis of polyorchidism, a rare congenital anomaly that has been reported infrequently in the veterinary literature; reports have been of animals with triorchidism, with the exception of 1 cat with 4 intraabdominal testes. Our report emphasizes that, although rare, polyorchidism should be considered in cryptorchid cats, or whenever penile spines are present in a previously castrated cat. Our case also highlights the value of checking for penile spines in a bilaterally cryptorchid cat if abdominal ultrasound is not an option to aid in surgical planning.