Polyorchid - Classification

Classification

Polyorchidism occurs in two primary forms: Type A and Type B.

• Type A: The supernumerary testicle is connected to a vas deferens. These testicles are usually reproductively functional. Type A is further subdivided into:
  • Type A1: Complete duplication of the testicle, epididymis and vas deferens.
  • Type A2: The supernumerary testicle has its own epididymis and shares a vas deferens.
  • Type A3: The supernumerary testicle shares the epididymis and the vas deferens of the other testicles.
• Type B: The supernumerary testicle is not connected to a vas deferens and is therefore not reproductively functional. Type B is further subdivided into:
  • Type B1: The supernumerary testicle has its own epididymis but is not connected to a vas deferens
  • Type B2: The supernumerary testicle consists only of testicular tissue.

Type A3 is the most common form of polyorchidism, and types A2 and A3 together account for more than 90% of cases. In 65% of cases, the supernumerary testicle is found in the left scrotal sac.