Scrotoschisis: An extremely rare congenital anomaly.

A rare case of unilateral scrotoschisis in a full term infant delivered by Caesarean section is reported.

INTRODUCTION

Testicular ectopia represents a well-recognised form of abnormal testicular descent.[1] Very rarely, the ectopic testis may be extracorporeal, having eviscerated through a defect in the scrotal wall. This anomaly is called scrotoschisis, and to the best of our knowledge only ten cases have been reported in the English literature.[2-5]

CASE REPORT

A 3-day-old male baby weighing 2.8 kg presented to us with congenitally exposed left testis since birth [Figure 1]. There were superficial inflammatory changes confined to the exposed part of the testis and the wound itself. The baby was delivered by Caesarean section at full term due to obstetric reasons. There was no history of iatrogenic injury to the scrotum during Caesarean section. Antenatal history and family history were not significant. Thorough clinical examination revealed no associated abnormality. The contralateral testis was normally placed and palpable in the scrotum. The vascularity of the eviscerated gonad was not compromised.

Figure 1

Congenitally exposed left edematous testis

An ultrasonography of the whole abdomen did not reveal any associated abnormality. Orchidopexy of the left testis was done within a few hours after admission. The defect was repaired in layers under general anesthesia after washing the area with warm normal saline. The patient had an uneventful recovery. The patient is doing well at 6 months follow-up.

DISCUSSION

Ectopic testes occur in a number of well-documented sites,[1] but extracorporeal ectopia is rare. In the situation described here, a scrotal defect allowed the descending testis to eviscerate, a condition referred to as scrotoschisis. Chun et al.[2] noted that experimental studies in rats showed that excision of future scrotal skin inhibited gubernacular migration, leading to ipsilateral testicular ectopia. This suggests that a normally developed scrotum is required to guide gubernacular migration before testicular descent. They further suggested that since, in scrotoschisis, the defect is medial, the scrotal skin required for gubernacular descent may arise more laterally or posteriorly. Gongaware et al.[3] suggested the failure of differentiation of scrotal mesenchyme leaving a defect where gubernaculum was covered only by a thin layer of epithelium. Lack of sufficient supporting structure results in rupture or avascular necrosis leading to the scrotal defect.

Early amnion rupture or the adhesion/band spectrum is often cited as a probable factor in scrotoschisis. Aberrant amnion bands, strands, or sheets can cause disruption of morphogenesis in the abdominal wall.[6] In his study, Davies[7] postulated that the amnion band sequence mechanism could have played a causative role in this abnormality. External mechanical compression due to arthrogryposis is also suggested as a cause of scrotoschisis by Lais et al. in their article.[8] Finally, the occurrence of meconial periorchitis is the best theory available. The proposed pathophysiology is the late rupture of the scrotal skin secondary to an inflaammatory reaction caused by exposure to meconium extruded from an intestinal segment and delivered to the scrotum during fetal life through the patent peritoneo-vaginal conduit (PVC).[9] Meconium residua have been described in the scrotal wall for three of the infants reported and one case of contralateral meconial periorchitis, diagnosed at 4 months of age as a paratesticular calcified mass, has been reported.[2] But in our patient there were no meconium residua present.

The constant site of the ruptures (medial and cranial scrotal wall) might be related to the anatomic location of the PVC (anteromedial to the cord and the testis). One case with an association between jejunal atresia and scrotoschisis has been reported[10] and the absence of intestinal abnormalities in most infants can be explained by fetal cicatrization of the original intestinal lesion without sequelae, a recognized phenomenon. In our patient, however, there was no evidence of persistent gubernacular bulb. The embryology of this curious anomaly remains unresolved. Most cases of scrotoschisis are unilateral and affect normal males[11] as seen in our case. Since the testis is unattached in this condition, torsion may occur, as in the study by Ameh et al.[4] resulting in gangrene. The eviscerated testes and scrotal defect should be covered with moist gauze to prevent desiccation and any torsion should be reversed. The operative treatment involves scrotal exploration and placement and fixation of the testis within the scrotum. Closure of the defect in two layers using absorbable sutures (Vicryl 5-0 in our case), transversely or longitudinally can be achieved after freshening the edges of the defect. The immediate prognosis is good, but long-term results are not available.[12]

In conclusion, scrotoschisis is a very rare genital abnormality, generally affecting normal-term male infants. The defect can be repaired with conventional trans-scrotal orchiopexy, with a good prognosis, except for cases of testicular torsion and irreversible ischemia.