Triorchidism is a rare congenital anomaly. Less than 200 cases of Triorchidism have been reported in literature [1]. According to previous studies, the extra testis is commonly present in the Scrotum (66%), inguinal canal (23%) or retroperitoneum (9%) [2]. A high number of patients with triorchidism are detected in the 20–40 year age group [1, 2, 4,5,6].
Compared to the right testis, the left testis is usually larger and has different topographic vascular anatomy and hence is more prone to divisions leading to polyorchidism [4]. Interestingly, Hassan et al. [5] have reported a case with triorchidism in the right testis. This can be explained by variations in testicular size.
Triorchidism, typically presents as a non-tender swelling of the scrotum. In a case studied by Aziz W et al., a 30-year-old male presented with a non-tender swelling of the testis and infertility. Infertility was attributed to faulty division of the testes [6].
Size of the testes solely depends on the division of testes. This is obvious by the variation of sizes reported in various studies. The present case report illustrates testes of equal size on both the sides. However, the supernumerary testis on the left side was smaller in size. Interestingly, Kheirandish et al. [1] reported a case where both the testes on the left side were of equal size and hence the supernumerary one was difficult to differentiate. In a case studied by Abduljabbar et al. [2], variation in size of both the testes on the left side was seen. However, the right testis was comparatively larger than both the left ones.
Primordial testis starts developing from the primitive genital ridge at about 6 weeks of gestational age. The primitive genital ridge lies medial to the mesonephric ducts. Shape of the testis is achieved by the 8th week. Epididymis and vas deferens start developing from the Wolfian duct (Mesonephric) around the same period. A horizontal or longitudinal plane duplication of the genital ridge takes place, which results in polyorchidism.
On the basis of embryological development, Leung gave the first classification (1988) which was later modified by Thum [7, 8].
- Type-1:
-
Division of the genital ridge only separating only a small part of the genital ridge that is not in contact with the rete testis. This results in supernumerary testis without an epididymis or vas and has shown no attachment to the usual testis
- Type-2:
-
Division of genital ridge occurs in the region where there is attachment of the primordial gonads to the metanephric ducts. Due to this, the supernumerary testis drains into the epididymis of regular testis and they share a common vas
- Type-3:
-
Complete transverse division of mesonephros as well as genital ridge, results in the supernumerary testis having its own epididymis and both epididymis of the ipsilateral testes draining into one vas
- Type-4:
-
Vertical division of the genital ridge and mesonephros results in complete duplication of testes, epididymis and vas
The case in the present report demonstrated Type 2 polyorchidism. This is also reflected by the absence of complaints other than non-tender swelling. However, Type 2 polyorchidism was reported in the study done by Hassan et al. and Aziz et al. [5, 6] which was reflected as reproductive abnormalities such as oligoasthenoteratozoospermia and infertility.
Management of polyorchidism depends on the age, location and organ architecture among other factors. A conservative approach with regular follow-up with emphasis on self-examination is carried out when maintenance of reproductive function is required. Resection is advised in case of suspicion of malignancy.