P0369 - A Rare Case of Metastatic Rectal Adenocarcinoma Associated With Imperforate Anus

Annie Shergill, MD¹, Karthik Mohan, DO¹, Luis Nasiff, MD^2
1Larkin Community Hospital, Miami, FL; ²Larkin Community Hospital, Palm Springs Campus, Miami, FL

Introduction: Imperforate anus (IA) or anal atresia is a congenital anorectal malformation with an absent anal opening at birth. It is treated with surgical intervention. Patients may have complications following corrective surgery such as rectal mucosal prolapse, fecal incontinence & anal stenosis. However it is not known if this condition is associated with a higher risk of colorectal cancer (CRC) as compared to patients at average risk of CRC. We present a rare case of metastatic rectal adenocarcinoma associated with IA.

Case Description/Methods: A 40 year-old male with past medical history of IA at birth (surgically repaired with posterior sagittal anorectoplasty and colostomy with eventual reversal), presented to the hospital with persistent rectal bleeding and intermittent shortness of breath for 1 month. Evaluation with CT chest, abdomen & pelvis without contrast showed multiple nodular lesions (concerning for metastases) in both lungs, rectal wall thickening (concerning for malignancy) & sigmoid colon diverticulosis. Patient did not have any family history of CRC. Patient underwent colonoscopy for evaluation of rectal bleeding & imaging finding of rectal wall thickening. Notably, patient had never undergone a colonoscopy previously. Colonoscopy showed diffusely ulcerated area in the rectum (Figure 1) from which multiple biopsies were taken, remaining exam showed mild sigmoid diverticulosis. Rectal biopsies showed rectal adenocarcinoma. Patient underwent CT guided biopsy of the lung lesion seen on CT chest which was confirmed to be metastases from primary rectal adenocarcinoma. Patient was referred to oncology and colorectal surgery for further management.

Discussion: IA belongs to a spectrum of congenital anomalies referred to as Anorectal Malformations (ARM). Most of these anomalies are surgically repaired. Patients may have long-term complications through out their life related to this diagnosis but the most worrisome emerging association is the incidence of CRC in this population, particularly seen in young patients. The exact mechanism behind this relationship is not well understood & warrants further review & research. Our case necessitates a discussion about considering CRC screening starting early on in life & at more frequent intervals in patients with IA & other form of ARMs.



Disclosures:


Annie Shergill, MD¹, Karthik Mohan, DO¹, Luis Nasiff, MD². P0369 - A Rare Case of Metastatic Rectal Adenocarcinoma Associated With Imperforate Anus, ACG 2023 Annual Scientific Meeting Abstracts. Vancouver, BC, Canada: American College of Gastroenterology.