Supernumerary kidney with ipsilateral cryptorchidism in a cat

Area of Science:

• Veterinary Medicine
• Developmental Biology
• Urology

Background:

• Congenital anomalies of the kidney and urinary tract can present with complex clinical signs.
• Cryptorchidism, the failure of testes to descend, is a known condition in domestic animals.
• Abdominal masses in cats require thorough diagnostic investigation.

Observation:

• An 8-week-old male domestic longhair cat presented with a palpable abdominal mass and cryptorchidism.
• Ultrasonography revealed a complex, septated, cystic mass near the right kidney.
• Surgical excision identified an ectopic kidney with a normal ureter, separate from the primary right kidney.

Findings:

• The excised abdominal mass was confirmed as a supernumerary (extra) kidney.
• The cat possessed a total of three kidneys: one normal left kidney, a normal right kidney, and a supernumerary right kidney.
• The supernumerary kidney was successfully removed, along with the cryptorchid testis and a hypoplastic ureter.

Implications:

• This case represents the first documented instance of a supernumerary kidney in a feline patient.
• Supernumerary kidney should be included in the differential diagnosis for abdominal masses in cats.
• Understanding rare congenital anomalies aids in accurate veterinary diagnosis and treatment planning.