S4001 A Bowel Invader: Endometriosis Causing Partial Colon Obstruction

Introduction: Endometriosis is a chronic disease characterized by presence of ectopic lesions predominantly in the pelvis, which can lead to pain, gastrointestinal or urinary symptoms, and infertility.1 The prevalence of colorectal involvement in women with endometriosis is estimated to be between 3%-37%.2 While the rectosigmoid region is the most affected site in the bowel, cases of intestinal occlusion due to endometriosis foci on the bowel are rare, with a reported prevalence of 0.1%-0.7%.2 This is a unique case of partial colon obstruction secondary to bowel-infiltrating endometriosis. Case Description/Methods: A 52-year-old woman with history of colon polyps and diverticulosis presented with subacute rectal bleeding, occasional bloating and cramping, and variable stool consistency. Initial colonoscopy revealed a severe sigmoid stricture, with inability to advance the colonoscope beyond the point of stricture. Computed tomography scan revealed a thickened and narrowed area of the distal sigmoid colon which raised concern for an underlying mass. A repeat colonoscopy was performed confirming the stricture, although no obvious mass was seen. She underwent a laparoscopic sigmoid colectomy, with pathology of sigmoid colon biopsies revealing endometriosis involving the colon wall. She developed postsurgical C. difficile, which was treated with antibiotics. Upon re-evaluation in clinic, the patient was asymptomatic and no longer had abdominal pain, rectal bleeding, or change in bowel habits. Discussion: Endometriosis commonly involves the gastrointestinal tract with a predilection for the rectosigmoid region. In rare cases, it can lead to strictures and bowel obstruction. In woman patients with changes in bowel habits which present in a cyclical manner, endometriosis should be considered on the differential diagnosis. Endometriosis should be considered as a multi-system disorder which may affect one or multiple regions of the gastrointestinal tract, either superficially or in an infiltrative manner. A thorough gynecologic history should be taken as a history of endometriosis or chronic pelvic pain may also support the diagnosis. References: 1. Griffiths MJ, Horne AW, Gibson DA, Roberts N, Saunders PTK. Endometriosis: recent advances that could accelerate diagnosis and improve care. Trends Mol Med. 2024;30(9):875-889. 2. Mușat F, Păduraru DN, Bolocan A, Constantinescu A, Ion D, Andronic O. Endometriosis as an uncommon cause of intestinal obstruction-A comprehensive literature review. J Clin Med. 2023;12(19):6376.