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Rectal duplication. B Kulkarni, SN Oak, SJ Karmarkar, AP Desai, SS DeshmukhDepartment of Paediatric Surgery, L T M G Hospital, Sion, Mumbai., Correspondence Address: PMID: 0010707712
Duplications of the alimentary tract are of a great rarity, particularly so in the rectum. Because of its rarity, the difficulty of making a correct diagnosis and of selection of proper approach for treatment, this entity bears a special significance. The present case report deals with a female newborn who presented with imperforate anus and a rectovestibular fistula and a mass prolapsing at the introitus. Complete excision of the mass was carried out through the perineal approach and the child then underwent, a PSARP for the correction of the rectal anomaly. Histology confirmed the mass to be a rectal duplication. Keywords: Abnormalities, Multiple, diagnosis,surgery,Anus, Imperforate, diagnosis,surgery,Case Report, Diagnosis, Differential, Female, Follow-Up Studies, Human, Infant, Newborn, Rectovaginal Fistula, diagnosis,surgery,Rectum, abnormalities,surgery,Treatment Outcome,
Rectal duplications are one of the rare congenital malformations. They have been reported to occur in 2-7% of all gastrointestinal duplications[1],[2]. The first case report of this rare anomaly is credited to Middledorf[3] who in 1885 described the occurrence of an egg-like cystic, mucus filled, retro-rectal mass in a 1-year-old girl. Intestinal mucosal lining and the presence of smooth muscle coat were also noted. Such lesions were also classified as teratomas[4] and as myoepithelial hamartomas[5]. However, they demonstrate three pathognomonic characteristics of alimentary tract duplications proposed by Ladd and Gross[6]. These include - (1) continuity or contiguity to some part of the alimentary tract. (2) a smooth muscle coat, and (3) a mucosal lining representative of alimentary tract. These lesions also precipitate multiple complications such as bleeding obstruction, infection and carcinomatous degeneration and hence correct diagnosis is vital. We present a case of rectal duplication which presented as prolapsing mass per introitus in a newborn having rectovestibular fistula and imperforate anus.
A 3.2 kg first born, full-term female child presented on first day of life with a protruding mass from left side of introitus. The child also had imperforate anus with a rectovestibular fistula. Baby appeared well hydrated and was not jaundiced. Abdominal examination was normal and no mass was palpable within. Urinary bladder was not distended. There was no evidence of ascites. The mass was solitary, appeared inflammed and was resembling a bunch of grapes and was bleeding on touch. [Figure:1] Initial diagnosis of Sarcoma Botryoides was made and the patient was further investigated. Haematological and biochemical profile was within normal limits. X-ray abdomen did not reveal any abnormality. CT Scan demonstrated that there was intra-pelvic extension of the mass. [Figure:2] Uterus and urinary bladder were normal. Rectovestibular fistula was also well outlined in CT scan. With conservative treatment for a few days oedema and inflammation, which was due to mass bathing in amniotic fluid subsided [Figure:3]. The mass at the introitus then showed an external opening on the surface. This could then be cannulated with a No. 8 FG feeding tube. Examination under anaesthesia followed and panendoscopy showed separate urethral, vaginal and rectal openings in the vestibule. The mass at the inroitus could then be entirely excised through perineal approach. it had a narrow base and a pedicle which extended approximately 2-3 cms. in the pelvis. This was lying in close proximity to rectum and vagina but had no communication with either. A sigmoid colostomy was done to divert the faecal stream from the rectovestibular fistula. Histo-pathology of the excised mass showed normal rectal mucosa with sub-mucous glands and muscle coat. At its distal end, presence of squamous epithelium was seen [Figure:4]. This confirmed the diagnosis of rectal duplication of tubular type. After 4 months, the patient underwent posterior sagittal anorectoplasty for the imperforate anus and colostomy closure followed after 3 weeks. Patient is now 8 months old and is doing well.
Rectal duplications are rare congenital malformations. The overall incidence quoted in various series of gastrointestinal duplications is 2-7%. Ladd and Gross had 1 case amongst their series of 18 cases of GI duplications[6], while Bower et al reported 2 in 78 cases of alimentary tract duplications[2]. LaQualia[9] reports only 11 cases of rectal duplications over a period of 50 years of review[8]. Several theories have been discussed to explain the origin of duplication[5],[10],[11]. Persistence of fetal gut diverticula, defective re-canalisation of the solid stage of primitive gut, miniature form of caudal twinning and in certain cases incomplete separation of the notochord from the endo-dermal tube, have been proposed as possible causes. In the large bowel the cystic variety occurs more commonly in relation to the rectum[11]. The tubular variety appears like a double lumen tube of variable length and may extend proximally towards the small bowel or distally to the anus. In rare instances, the duplication prolapses anteriorly in the vestibule and poses diagnostic dilemma as ‘tumour of vulva’[1]. The presentation of the rectal duplication depends on: (1) the size, and therefore the mass effect of the duplication, (2) fistulization, (3) infection in the duplication, (4) the presence of ectopic gastric mucosa and ulceration[12] and malignant change. Because these duplications are lined by mucosa characteristic of gastrointestinal tract, they get filled with a clear, colourless mucus. Secondary infection can lead to tenderness and bleeding. Urinary tract symptoms are not very common though very large lesions can lead to bladder compression[9]. Tubular duplications rarely may pro-lapse through rectum and then are misdiagnosed as haemorrhoids[8]. Malignant degeneration in rectal duplications was first reported by Ballantyne in 1932 and adenocarcinomas are known to develop in adulthood[13]. The treatment of rectal duplications is surgical excision. A transanal or transcoccygeal approach can be adopted for excision. For larger or complicated lesions a posterior sagittal incision is favoured. If there is an extension in the abdomen, rarely an abdomino-perineal approach may be required. If complete excision is not possible then at least complete extirpation of the mucosa must be undertaken. Infected duplications may need initial drainage followed by a staged resection. In summary the case report describes a very rare occurrence of a rectal duplication in a new-born having impreforate anus, and presenting as a pro-lapsing mass at the introitus.
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