Synchronous Development of Hemiscrotal Tissue in the Orthotopic and Ectopic Locations in Association with other Urological Anomalies

Abstract

Ectopic scrotum is a rare form of congenital scrotal anomaly that is rarely encountered in pediatric surgical practice. Herein, we report an infant with a unilateral ectopic suprainguinal scrotum associated with undescended testis and multicystic dysplastic kidney. The case is reported in view of rarity of this anomaly in the general pediatric population.

INTRODUCTION

In the context of male genitalia, isolated congenital anomalies of the scrotum are rare. On the other hand, conditions such as bifid scrotum and penoscrotal transposition that are associated with severe hypospadias and disorders of sexual differentiation are not that uncommon.[1] Ectopic scrotum is an extremely rare congenital anomaly of the scrotum where the hemiscrotum and the testis are malpositioned, although cases with cryptorchidism are also known. The etiology of ectopic scrotum is not defined clearly. We present an infant having an ectopic scrotum with undescended testis (UDT) and unilateral multicystic dysplastic kidney (MCDK) in view of rarity of this form of scrotal anomaly and also present to highlight the management options for the same.

CASE REPORT

A 6-month-old boy, with no antenatal or perinatal complications, was brought to the pediatric surgery outpatient department with an appendage on the right-sided groin, noted since birth. Parents were concerned as the appendage appeared as an extra penis. Further inquiry revealed that the child was passing urine normally only from the orthotopic penis. There was no change in size, color, or discharge from the appendage. There was no early morning erection seen in the appendage, and no discharge was ever noted from the appendage. Systemic examination was normal. Local examination revealed a conical appendage with a hyperpigmented rugose skin on the right side of the pubic region [Figure 1a]. The base was 3 cm oblong. The appendage was mobile with the skin and not fixed to underlying structures. The penis was grossly normal. The left testis was palpable in the well developed left hemiscrotum. However, the right hemiscrotum was hypoplastic and empty. The right testis was found palpable in the right inguinal region. An ultrasound of the abdomen revealed that the right renal tissue was replaced with cysts. A diuretic renogram suggested a right nonfunctioning kidney with normally functioning left kidney. Magnetic resonance imaging of the abdomen and pelvis demonstrated a MCDK in the right side with right UDT located at the superficial ring. The left kidney was normal and so was the penis with normal corporal bodies.

Figure 1.

(a) Clinical image showing the appendage on the right side of the pubic area associated with a hypoplastic right hemiscrotum. (b) Postoperative photograph showing the scar and the right hemiscrotum housing the small testis

A diagnosis of an ectopic right hemiscrotum with a palpable UDT was made. The child was planned for right ectopic scrotum excision with or without orchiopexy. After excising the ectopic partial scrotum, an underlying thick cord-like tissue akin to the gubernacular tissue was found that led us to the right UDT and associated patent processus vaginalis. The right testis was smaller than the left side. We could achieve adequate mobilization by dissecting in the area outside the superficial ring without having to open the inguinal canal. Herniotomy was performed. The testis could reach a subdartos pouch created in the small right hemiscrotum [Figure 1b]. The child was discharged within 6 h of operation in good health. The child was found to be asymptomatic in the first follow-up visit. The last follow-up was 9 months after the procedure, and the examination showed a right intrascrotal testis [Figure 2]. The child is planned for long-term follow-up, keeping in mind that the child also has a right MCDK.

Figure 2.

Clinical image of the patient 9 months after the operation showing intrascrotal testis on the operated side

DISCUSSION

Ectopic scrotum is a very rare type of scrotal congenital anomaly wherein a unilateral hemiscrotum is abnormally positioned along the inguinal canal, the perineum, or the thigh. The most common site is the suprainguinal location, as was in our case.[2] Other sites are inguinal, infrainguinal, perineal, femoral, and medial thigh. The ipsilateral testis is usually present inside the ectopic scrotum; however, reports of associated cryptorchidism, as in our case, are also present in the literature. The common associated anomalies are renal and ureteral anomalies, while skeletal defects, imperforate anus, hypospadias, diphallia, penile torsion, exstrophy bladder, patent urachus, and cleft palate have also been reported.[1,3] The upper urinary tract anomalies are associated more with the suprainguinal variant, while they are uncommon with the infrainguinal types of ectopic scrotum.[1,4] The present child also had associated ipsilateral urogenital anomalies.

The embryological explanation on the mechanism of ectopic scrotum is unclear. It is hypothesized that it is a defect of migration and midline fusion of labioscrotal swelling. The scrotal development commences at 4 weeks of gestation with the appearance of paired labioscrotal swellings, which migrate inferomedially by 12 weeks, to fuse in midline with the formation of medial scrotal raphe. Simultaneously, there starts the development of gubernaculum from mesenchymal tissue by the 5^th week of gestation, which is inserted into labioscrotal swelling and facilitates the descend of testis.[3] It has been postulated that disturbed interaction between gubernaculum with labioscrotal folds or aberrantly stabilized gubernaculum can lead to ectopic scrotum.[5] The ipsilateral renal anomaly, which results from defective induction of metanephric tissue due to failure of ureteric bud formation, is hypothesized to be resulting from unknown local factors, which impede both the scrotal migration and the ureter bud development at around the 5^th week of gestation.[1]

It seems that the biological signal for the scrotum development is two-pronged; it is linked to the descending testis as well as to local factors and of course a closely coordinated mechanism between the two. Herein, one of these prongs or factors led to the development of the orthotopic right hemiscrotum, while the second set of factors led to the ectopic right hemiscrotum. The descent of the testis, however, is influenced by only one of these factors which dominated in the context of the index case. The report merits further research into additional, yet unearthed factors which could be involved at the interface of two very important developmental phenomena, namely, the development of the scrotum and testicular descent.

A spontaneous descent of the testis is not expected for ectopic scrotum; thus, surgery becomes the definitive treatment in ectopic scrotum. If the size of the orthotopic hemiscrotum is adequate to house the testis, as was in our case, a simple excision of ectopic scrotal tissue with orchiopexy is appropriate. However, when the scrotal tissue is scanty in the normal location, then a flap scrotoplasty followed by orchidopexy as a second stage becomes an option to provide a scrotal skin cover during subsequent orchidopexy.[6]

The differential diagnosis to ectopic scrotum is an accessory scrotum, where ectopic scrotal tissue is noted in addition to normally developed scrotum as well as descended testis, with the most common location being the perineum. The accessory scrotum is associated with perineal lipoma, hypospadias, diphallia, anorectal malformation, or vertebral, anal, cardiac, tracheoesophageal, renal, and limb anomalies. On the contrary to classical ectopic scrotum, our case had a poorly developed ipsilateral hemiscrotum without any testis within. Despite being hypoplastic, we could manage to create a subdartos space and place the UDT into the hemiscrotum without significant tension in a single stage without requiring flap transfer.

A rare case of ectopic scrotum with UDT and MCDK is reported. After a thorough workup to document associated anomalies, a surgical option should be chosen depending on the aberrant anatomy of any particular case. This may range from a simple excision and orchidopexy to a staged procedure requiring flap scrotoplasty and subsequent orchidopexy.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.