Ruptured rectal duplication with urogenital abnormality: Unusual presentation.

Rectal duplication (RD) accounts for 5% of alimentary tract duplication. A varied presentation and associated anomalies have been described in the literature. Antenatal rupture of the RD is very rare. We present an unusual case of a ruptured RD associated with urogenital abnormalities in newborn male. We are discussing diagnosis, embryology, management and literature review of ruptured RD.

INTRODUCTION

Gastrointestinal tract duplications are rare congenital anomalies. They may occur throughout the alimentary tract and only 5% of them occur in the rectum.[1] Rectal duplication (RD) can be located posteriorly (most common), anteriorly or laterally, accordingly the presentation varies. The diagnosis of a RD can be made after clinical examination and preoperative imaging (contrast enema, CT/MR imaging or transanal ultrasound). Surgical excision is curative and approach depends upon the position of the cyst and its relationship with adjacent structures. The goals of treatment are complete excision of RD when feasible and extirpation of mucosal lining in the rest without damaging the normal rectum and its continence. Antenatal rupture of RD is very rare and only a few cases are reported. We are discussing a case of a ruptured RD (anteriorly on the perineum) with complex urogenital abnormality and its management.

CASE REPORT

A 6-hour-old full-term male baby was referred to our hospital with complaints of fleshy mass over the perineum and abnormal genitalia noted at the time of birth. He was born by normal vaginal delivery, weighed 2.5 kg and had an uneventful antenatal period. On examination, opened up mucosa lined patch was protruding at perineal region extending up to the penoscrotal area. He also had penoscrotal hypospadias with penoscrotal transposition and ectopic right scrotum [Figure 1a and b]. Anal opening was present at orthotopic site but anterior half of the anal opening was replaced by mucosa lined patch which was continuing onto the normal rectum. On further evaluation he had solitary right kidney without hydronephrosis, voiding cystourethrogram had been performed which was normal. There were no associated cardiac or spinal anomalies. The child underwent a staged reconstructive procedure. A protective colostomy with a biopsy of the perineal fleshy patch was done in the neonatal period and the biopsy showed rectal mucosa with sparse urothelieal component. Subsequently excision of RD was performed by an anterior sagittal approach [Figure 2], the full thickness rectal patch was dissected free from perineal skin and mobilized from underlying rectum. There were no attachment with underlying urethra and could be easily dissected off from the penoscrotal region without injuring normal urethra. The duplication cyst was in close proximity with the native rectum but had not shared the common wall, hence could be removed completely without injuring normal rectum. The reconstruction of the perineum was accomplished by primary closure of the resultant perineal defect except for a small area which was left to heal secondarily. At the same time correction of penoscrotal transposition and ectopic scrotum was also done. Later, colostomy was closed and hypospadias was corrected by tubularized incised plate (TIP) urethroplasty repair [Figure 3]. Post operatively the child had developed fistula at the midpenile region which was repaired after 6 months. Child was under follow up, was doing well at last visit and has good continence for urine and stool.

Figure 1

Clinical presentation. (a) ruptured RD over the perineum (white arrow) and ectopic right scrotum (black arrow) along with penoscrotal transposition. A normal anal opening (blue arrow) was present at the orthotopic site. (b) RD mucosa (white arrow) which was extending up to penoscrotal area with adjoining mucosa, penoscrotal hypospadiac meatus (black arrow) along with uroepithelial-lined (blue arrow) urethral plate. The black-dotted mark circumferentially is showing a line of incision

Figure 2

Intraoperative image; RD excised completely and both scrotum mobilized for reconstruction

Figure 3

Postoperative outcome; final outcome after urethroplasty. The perineal wound (black arrow) can be seen, healed by secondary intention

DISCUSSION

Distal hindgut duplications are rare forms of intestinal duplications. These are classified as anal canal duplications and rectal duplications (RDs). RDs are further classified as type I (cystic) and type II (tubular). Most of them are type I and in 90% of cases do not communicate with the rectum.[2] The symptoms depend on the mass effect, the presence of a fistula, infection, ectopic gastric mucosa, ulceration and malignant degeneration. The presentation of RD includes intestinal obstruction (constipation) or bladder outlet obstruction (dysuria, pelvic pain), discharge/bleeding from the rectum or perianal fistula.[345]

Extraluminal communication of RD present as a protruding mass or fistula while intraluminal communication presents with discharge or bleeding per rectum.

Multiple theories have been proposed regarding the etiology of duplications. According to Veenklass, duplications result from defective adherence of the endoderm to the notochord while Lewis et al. proposed “pinching off” of diverticula from the tailgut and Beach et al. proposed aberrant recanalization of the alimentary tract.[678] During 4th to 10th week of gestation urorectal septum descends and divide the cloaca, at the same time mesenchymal ingrowth occurs in the cloacal membrane.[9] The defect in any of these structures or combination determines the form of the anomaly encountered and its associated defect.

Our case is unique as the combination of a rectal duplication (which was ruptured antenataly) with associated complex urogenital anomaly was not described earlier. The other described cases in the literature with ruptured RD were associated with exstrophy, hypospadias and anorectal malformation.[10]

In our case, it is possible that the cyst became significantly enlarged in utero resulting in weakness of surface ectoderm secondary to pressure effects and resulted in antenatal rupture. The development of a duplication cyst, aberration in descent of urorectum septum, displacement of surrounding structure during developmental phase in utero may explain the severity of anomaly and associated abnormality. In this case the development of rectal duplication would have hampered the growth of developing urogenital structure and might have caused this complex urogenital abnormality. The urothelial components in the biopsy tissue suggest that anamoly would have occurred at a very early stage of embryology when urogenital structure and hind gut structure were in close proximity during the cloacal division. Also, the intact perineal body and anal sphincter complex indicates that anomaly would have occurred just at the point of fusion between urorectal septum and cloacal membrane, hence not affected the development of the continence mechanism.

In view of the rarity of the ruptured duplication cyst at the newborn period it is difficult to diagnose it emphatically in a neonate but in this case the normal anal opening, clinical appearance of protruding segment and histology of that segment were suggestive of duplication. The differential diagnosis for a ruptured RD includes rectal prolapse and intussusception, both can be ruled out by clinical examination alone.

We undertook a staged reconstruction of the anomaly with a protective colostomy in view of the risk of infection, possibility of sharing a common wall between the RD and native rectum. We feel that staged reconstruction will result in a good functional outcome and satisfactory cosmesis

CONCLUSION

RD is a very rare type of alimentary tract malformation and presentation with ruptured duplication is exceptional. It requires proper evaluation for associated abnormality. We recommend a staged correction for this type of complex anomaly. It provides adequate time to plan the appropriate procedure and offers satisfactory cosmesis and good functional outcome in long term.