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Polyorchidism is the incidence of more than two testicles. It is a very rare congenital disorder, with less than 200 cases reported in medical literature and 6 cases (two horses, two dogs and two cats) in veterinary literature 〔 〕 Polyorchidism is generally diagnosed via an ultrasound examination of the testicles. However, the diagnosis of polyorchidism should include histological confirmation. The most common form is triorchidism, or tritestes, where three testicles are present. The condition is usually asymptomatic. A man who has polyorchidism is known as a polyorchid. == 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.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Polyorchidism」の詳細全文を読む スポンサード リンク
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