Bilobed testicle diagnosed by ultrasound in a 9-year-old boy

Bilobed testis is an extremely rare congenital malformation, and even rarer on the right side. Only 7 cases have been reported in the literature. We describe the case of a 9-year-old boy with a right bilobed testicle confirmed on ultrasound and discovered incidentally as a mass on physical examination. The aim of our work is to consider the bilobed testicle as a differential diagnosis of a testicular mass despite its rarity and to show the importance of ultrasound and MRI for its definitive diagnosis to avoid unnecessary surgery.


Introduction
Bilobed testis is an extremely rare congenital malformation in children, more common on the left side [1 ,2] . Although the etiology is still unknown, it is speculated that this malformation may be an incomplete expression of polyorchidism with less than 200 cases reported [1 ,3] . It is overall a benign condition according to previous studies [3 ,4] , but it may lead to a higher risk of torsion or even malignancy [4] . Its treatment is so far conservative, but it is difficult to evaluate the long-term development of the disease due to its rarity [4] . Only 7 cases have been reported in the literature to date [4] .
We describe here a case of right bilobed testis in a 9-yearold boy confirmed by scrotal ultrasound.

Case report
A 9-year-old boy with no particular personal or family history was referred to the department of pediatric surgery and radiology for a right scrotal painless mass, not increasing in volume, with no inflammatory signs. It has appeared 2 years prior to his admission.
The clinical examination revealed a round, painless, mobile mass, well-limited, in the upper pole of the right testicle. The rest of the physical examination didn't reveal anything particular. the Doppler ultrasonography measuring 10 × 6.5 × 5 millimeters. The mass had a similar size and echotexture with normal adjacent testis ( Fig. 1 ). The left testicle was of a similar size, measuring 21 ×14 ×10 millimeters with normal vascularity and normal-appearing of both epididymis and spermatic cords.
Because of the echogenicity corresponding to a testicular structure and the absence of complications such as testicular torsion, the diagnosis of bilobed testicle was retained.
Conservative treatment was indicated with quarterly ultrasound monitoring of the patient.

Discussion
Bilobed testis is an extremely rare testicular malformation [1] , several researches have been made to explain its mechanism, but at the moment no theory can be confirmed [1] . Though we can assume that it is an incomplete form of polyorchidism [3] , it may result from incomplete division of the genital ridge by the peritoneal band [4] . It is much rarer and more interesting to study [2] . However, the main distinguishing feature between these 2 diseases in the case of polyorchidism, is that the supernumerary testicle is smaller than the main testicle [3] . It is usually asymptomatic [5] . It has been associated with several pathologies such as malignancy, inguinal hernia and testicular torsion [3] .
According to previous studies the bilobed testicle is considered a benign entity, however a debate still persists over the risk of torsion and malignancy on bilobed testicle cases [3 ,4] .
Historically, the definitive diagnosis of polyorchidism was made by surgical exploration, nowadays ultrasound and MRI are sufficient to diagnose polyorchidism including bilobed testicle.
The management of polyorchidism still remains controversial [1 ,4] . Some authors recommend conservative treatment [1] while others have recommended surgical management including partial orchiectomy or orchidopexy depending on the complication, based on the suspicion of malignancy and the high prevalence of testicular torsion [5] .
As mentioned above in the case report, in our experience, given the absence of complications, surgical exploration was not necessary.

Patient consent
Written and informant consent for publication of the case was obtained from the patient.