Polyorchidism

Polyorchidism (or supranumerary testes) refers to the presence of more than two testes and is a very rare congenital anomaly. The supernumerary testis can be usually located inside the scrotum (75% of the patients) or less commonly in the inguinal canal, the retroperitoneum, or the abdominal cavity.1-3

A rare condition, only 140 cases were reported until 2013.

Polyorchidism is asymptomatic in the majority of patients. Some patients may present with scrotal pain, scrotal swelling, hydrocoele, varicocoele, epididymitis, infertility, testicular malignancy, or testicular torsion 2Testicular torsion is the most commonly encountered complication of polyorchidism 3.

Clinical examination usually reveals that the testes are normally descended inside the scrotum. However, a nodule can be palpable inside the affected hemiscrotum. This nodule is easily differentiated from the normal testes.  

As polyorchidism usually causes no symptoms, it is often found incidentally during surgery for inguinal hernia, testicular tumour, or torsion 1. Polyorchidism is commonly associated with inguinal hernia (24%), undescended testis (22%) and microlithiasis 1.

There are several types of this condition with triorchidism being the most common. In this type, there are three testes with the supernumerary being situated on the left (in 65% of the cases). In 4.3% of patients with polyorchidism, there is bilateral involvement with four testes.

Aetiology

Polyorchidism is a developmental anomaly with abnormal division of the genital ridge. The genital ridge can be longitudinally or transversely divided or duplicated before the 8th week of fetal development. The Wolffian duct may be duplicated as well.

Classification

Polyorchidism has been recently classified in two major types (A and B) based on the venous drainage of the testicle.

The major types have subtypes:

  • in type A polyorchidism, the supernumerary testicle is drained by a separate vas deference and consequently has reproductive potential
    • type A3 represents the most frequent subtype and represents 90% of all cases of polyorchidism
  • in type B polyorchidism, the supernumerary testicle is not drained by a vas deferens and thus has no reproductive potential 1
Ultrasound

Scrotal ultrasonography demonstrates normal echogenicity of the testes. The supernumerary testis/testes can be seen as a solid nodule which is isoechoic to the testes. This nodule is usually located lower than the normal testes and is smaller. Hydrocoele is present in 9% of patients 1

Color or power Doppler ultrasonography reveals normal blood flow in both normal testes and in the supernumentary testis 4

MRI

When ultrasonography does not provide a conclusive diagnosis, MRI can be very helpful. The supernumerary testis has the same signal intensity with the normal testes: intermediate signal intensity on T1-weighted images and high signal intensity on T2-weighted images 4

The management of patients with polyorchidism is under debate. Removal of a supernumerary or ectopic testis with orchiectomy is recommended by some due to the high risk of malignancy (4-7%). Cryptorchidism is considered to be the greatest risk factor for malignancy in patients presenting with polyorchidism.

Alternative management includes preservation of an incidentally found supernumerary testis and long term follow-up of the patient. Treatment can be based on the presence or not of a vas deferens to the supernumentary testicle 2-4.   

The term "polyorchidism" derives from the Greek root "πολυ-" (poly-) meaning plenty and the word "όρχις" (orchis) meaning testicle and was firstly used by Lane in 1895. 

Possible differential considerations include:


Abdominal and pelvic anatomy
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Article Information

rID: 26484
System: Urogenital
Section: Anatomy
Synonyms or Alternate Spellings:
  • Triorchidism
  • Supernumerary testes
  • Supernumerary testis

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    Figure 1: polyorchidism classification
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    Case 1
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