The human body typically develops with two testicles, a common understanding of male anatomy. In rare instances, however, a person can be born with more. This uncommon occurrence is a recognized medical phenomenon, known as polyorchidism, which involves the presence of additional testicular tissue.
What is Polyorchidism
Polyorchidism refers to the presence of more than two testicles, a rare congenital condition. The most frequently observed form is triorchidism, meaning three testicles are present. Fewer than 200 cases have been reported in medical literature.
The condition is categorized into two main types: Type A and Type B. In Type A polyorchidism, the extra testicle is connected to a vas deferens, giving it potential reproductive function. Type A is further subdivided based on the extent of duplication of the epididymis and vas deferens. In contrast, Type B polyorchidism involves an extra testicle not connected to a vas deferens, and therefore lacks reproductive function.
How Extra Testicles Form
The precise reasons for the formation of extra testicles are not entirely understood. One theory suggests polyorchidism results from an abnormal division of the genital ridge during early fetal development, specifically before the eighth week of gestation. The genital ridge is the precursor tissue from which the testicles develop. This abnormal division is a leading explanation for this developmental anomaly.
Detection and Diagnosis
Polyorchidism is often discovered incidentally during a physical examination or imaging studies. Patients may present with a painless scrotal mass, leading to further investigation. The primary diagnostic method is scrotal ultrasonography.
An ultrasound can identify the extra testicle, which appears similar to a normal testicle. This helps differentiate it from other scrotal masses like lipomas or adenomatoid tumors. Magnetic resonance imaging (MRI) can provide additional information or confirm ultrasound findings.
Medical Considerations and Management
Once diagnosed, the medical management of polyorchidism involves considering potential risks and choosing an appropriate strategy. Extra testicles carry an increased risk of complications, including testicular torsion and malignancy, such as germ cell tumors. The risk of torsion in extra testicles is higher than in normal testes, with some studies reporting rates up to 15%.
Management strategies range from conservative surveillance to surgical removal. For asymptomatic extra testicles without signs of malignancy, regular follow-up with physical examinations and imaging is often recommended. Surgical removal may be considered if there is suspicion of malignancy, if the extra testicle is undescended (cryptorchid), or if it is located outside the scrotum (e.g., in the abdomen or inguinal canal), as these factors increase the risk of cancer. The decision for surgery or surveillance also depends on factors like the patient’s age and reproductive potential.