Rectal adenocarcinoma following imperforate anus: A rare case report

Abstract

Background: Anorectal malformations are a rare presentation. The standard treatment modality for imperforate anus is surgery. The abdominoperineal pull-through procedure was popular in the past for this malformation, but, with recent advancement, the posterior sagittal anorectoplasty and colostomy as a staged procedure are other options. Chronic constipation following pull-through procedures for imperforate anus may also lead to degeneration of the anorectal segment. Case Presentation: A 28-year-old male presented with the complaint of on and off constipation and painful defecation since childhood. The patient had a history of imperforate anus congenitally, for which a pull-through procedure was done after birth at another hospital. He underwent multiple surgeries for constipation. During this time period, the patient had constant complaints of difficulty in defecation and constipation, for which he used to use Hager’s dilators to dilate the anal canal. He also used per rectal enema and suppositories. His digital rectal examination showed narrowed anal opening. Colonoscopy was planned, which showed ulcerated and necrotic area at 6–8 cm from anal verge. Biopsy came out to be moderate-to-poor differentiated adenocarcinoma with signet ring cell differentiation. His computed tomography scan was performed, which showed circumferential mural thickening starting from the anal verge to the rectosigmoid junction with local infiltration to prostate, bilateral levator ani, and posterior sacral space. The patient was given a diversion colostomy and was referred for neoadjuvant chemoradiotherapy. Conclusion: All patients undergoing pull-through procedures should be closely followed in a multidisciplinary unit with interval colonoscopy for the early detection and prompt management of rectal cancer.