Background
Anorectal malformations are a rare presentation. About 1 in every 10,000 children is born with imperforate anus [1]. In the past, the abdominoperineal pull-through procedure was used to correct these malformations. However, with recent advancement, the posterior sagittal anorectoplasty has been used with better results to correct this deformity and was described for the first time by Levitt et al. in 2012 [2]. A colostomy is an add-on treatment modality that is considered when the patient has co-existing rectobulbar urethral fistula, rectal atresia, rectobladder neck fistula, and imperforate anus without fistula. However, the risk associated with surgery results in long-term morbidity and post-operative sequelae, which includes fecal soiling, constipation, and fecal incontinence. There has also been extremely rare report of malignancy following pull-through procedures within the anorectal segment as well [3–6].
Colorectal carcinoma is associated with multiple predisposing factors. These include genetic, dietary, and environmental factors. The chronic exposure of the rectal mucosa to carcinogens following a chronic constipation is associated with distal colonic and rectal cancer.
Case Presentation
A 28-year-old male presented with the complaints 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 8 years of age, the patient had an ileostomy made along with another anal procedure. This ileostomy was reversed after 6 months. At 15 years of age, the patient had another ileostomy made for absolute constipation also reversed after 6 months. After the closure of stoma, 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 and also used per rectal enema and suppositories. A family history was not significant for colorectal cancer.
There was a narrowed anal opening on the digital rectal examination.
Before 2 years, his first colonoscopy showed non-obstructing narrowing at anal verge with hard and fibrotic mucosa. A biopsy was unremarkable. We planned for another colonoscopy that showed ulcerated and necrotic area at 6–8 cm from the anal verge. The biopsy came out to be moderate-to-poor differentiated adenocarcinoma with signet ring cell differentiation.
His computed tomography scan and magnetic resonance imaging were 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, and stage III rectal carcinoma (Figure 1).
The patient was given a diversion colostomy and was referred for neoadjuvant chemoradiotherapy.
Discussion
We presented the case of a 28-year-old patient with no family history of colorectal cancer presenting to us with signet ring cell adenocarcinoma of the rectum following a pull-through procedure. About 0.1%–2.4% of cases of all colorectal cancers present with primary signet ring cell differentiation [7]. The 5-year survival rate is found to be 9.1% in a study conducted by Messerini et al. [8]. In a study conducted by Anthony et al., 72.4% of patients with primary signet ring cell carcinoma present with distant metastasis or nodal involvement at the time of presentation, of which 75.8% died of advanced disease in an average time of 18 months [7]. This highlights the tendency of signet ring cell adenocarcinoma to involve retroperitoneal lymph nodes being a major contributory factor to failure in response to therapy.
MRI of Pelvis showing circumferential mural thickening from the anal verge to the rectosigmoid junction with local infiltration to prostate, bilateral levator ani and posterior sacral space.
A review of articles has reported that overall 12 such cases have been reported [9]. In one study conducted by Midrio et al. [10] in 2016, two cases of imperforate anus presented with mucinous adenocarcinoma of the rectum at a young age following a pull-through procedure in the past. However, these cases had rectourethral and rectobulbar fistula at presentation. Similarly, Mukawa et al. and Symons et al. [3,4], in their case report, documented the finding of adenocarcinoma of the rectum following a pull-through procedure for rectobulbar and rectourethral fistula.
Posey et al. [11] reported a case of signet ring cell adenocarcinoma as a consequence of chronic exposure of urine as an irritant to rectal mucosa in a patient of imperforate anus with coexisting neurogenic bladder.
Symons et al. and Gupta et al. [4,6] reported the occurrence of para-neorectal adenocarcinoma, suggesting that it arises most likely from remnants of rectal mucosa left outside the neorectum following pull-through procedures. Another case study done by Mukawa et al. [3] stated that fecal incontinence as a complication to pull through procedure leads to the chronic source of irritation to rectal mucosa, hence leading to the development of anorectal carcinoma.
In this study, the patient had a long history of constipation following the pull-through procedure. The development of rectal adenocarcinoma, in this case, is likely a result of the chronic exposure of the rectal mucosa to fecal content due to increased transit time. This might be a predisposing factor leading to the malignant degeneration of the already compromised pulled through segment of the anorectum.
However, evidence is not conclusive, and more studies are required to evaluate the exact pathophysiology behind the occurrence of adenocarcinoma of anorectum following pull-through procedures.
Conclusion and Rationale
We recommend that 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.
What is new?
Anorectal canal malformations are a rare presentation. About 1 in every 10000 children is born with Imperforate anus. Therefore, information and knowledge is required for the proper management. This is a intresting case report of a patient with carcinoma rectum due to surgical procedure done in childhood for anorectal malformation.