Polyorchidism is the incidence of more than two

testicle A testicle or testis (plural testes) is the male reproductive gland or gonad in all bilaterians, including humans. It is homologous to the female ovary. The functions of the testes are to produce both sperm and androgens, primarily testoste ...

s. It is a very rare

congenital disorder A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities ca ...

, with fewer than 200 cases reported in medical literature and six cases (two horses, two dogs and two cats) in veterinary literature. Polyorchidism is generally diagnosed via an

ultrasound Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies ...

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 The vas deferens or ductus deferens is part of the male reproductive system of many vertebrates. The ducts transport sperm from the epididymis to the ejaculatory ducts in anticipation of ejaculation. The vas deferens is a partially coiled tube ...

. These testicles are usually reproductively functional. Type A is further subdivided into: ** Type A1: Complete duplication of the testicle, epididymis and

. ** 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.

Numeric system

An older system of classification structures polyorchidism into similar types, but with no subdivision between connected and disconnected testicles: * Type 1: The

supernumerary Supernumerary means "exceeding the usual number". Supernumerary may also refer to: * Supernumerary actor, a performer in a film, television show, or stage production who has no role or purpose other than to appear in the background, more commonl ...

testicle lacks an epididymis and

and has no connection to the other testicles. * Type 2: The supernumerary testicle shares the epididymis and the vas deferens of the other testicles. * Type 3: The supernumerary testicle has its own epididymis and shares a vas deferens. * Type 4: Complete duplication of the testicle, epididymis and vas deferens.

Cause

Complications

Most cases of polyorchidism are asymptomatic, and are discovered incidentally, in the course of treating another condition. In the majority of cases, the supernumerary testicle is found in the scrotum. However, polyorchidism can occur in conjunction with

cryptorchidism Cryptorchidism, also known as undescended testis, is the failure of one or both testes to descend into the scrotum. The word is from Greek () 'hidden' and () 'testicle'. It is the most common birth defect of the male genital tract. About 3% of ...

, where the supernumerary testicle is undescended or found elsewhere in the body. These cases are associated with a significant increase in the incidence of testicular cancer: 0.004% for the general population vs 5.7% for a supernumerary testicle not found in the scrotum. Polyorchidism can also occur in conjunction with infertility,

inguinal hernia An inguinal hernia is a hernia (protrusion) of abdominal-cavity contents through the inguinal canal. Symptoms, which may include pain or discomfort especially with or following coughing, exercise, or bowel movements, are absent in about a third ...

testicular torsion Testicular torsion occurs when the spermatic cord (from which the testicle is suspended) twists, cutting off the blood supply to the testicle. The most common symptom in children is sudden, severe testicular pain. The testicle may be higher than ...

epididymitis Epididymitis is a medical condition characterized by inflammation of the epididymis, a curved structure at the back of the testicle. Onset of pain is typically over a day or two. The pain may improve with raising the testicle. Other symptoms may i ...

hydrocele testis A hydrocele testis is an accumulation of clear fluid within the cavum vaginale, the potential space between the layers of the tunica vaginalis of the testicle. It is the most common form of hydrocele and is often referred to simply as a "hydrocele ...

and

varicocele varicocele is an abnormal enlargement of the pampiniform venous plexus in the scrotum. This plexus of veins drains blood from the testicles back to the heart. The vessels originate in the abdomen and course down through the inguinal canal as p ...

. However, it is not clear whether polyorchidism causes or aggravates these conditions, or whether the existence of these conditions leads sufferers to seek medical attention and thus become diagnosed with a previously undetected supernumerary testicle.

Management

Because polyorchidism is very uncommon, there is no standard treatment for the condition. Prior to advances in ultrasound technology, it was common practice to remove the supernumerary testicle. Several cases have been described where routine follow-up examinations conducted over a period of years showed that the supernumerary testicle was stable. A

meta-analysis A meta-analysis is a statistical analysis that combines the results of multiple scientific studies. Meta-analyses can be performed when there are multiple scientific studies addressing the same question, with each individual study reporting me ...

in 2009 suggested removing non-scrotal supernumerary testicles because of the increased risk of cancer, and regular follow-up in the remaining cases to ensure that the supernumerary testicle remains stable.

References

External links

{{Authority control Supernumerary body parts Congenital disorders of male genital organs Rare diseases Testicle Intersex variations