Terminal ileal endometriosis masquerading as Crohn’s disease: a rare cause of small bowel obstruction and perforation in a middle-aged woman

Endometriosis is a chronic inflammatory condition affecting 5–10% of women of reproductive age, most commonly involving pelvic organs. Gastrointestinal endometriosis, particularly at the terminal ileum, is rare and can clinically mimic other conditions such as Crohn’s disease, posing significant diagnostic challenges. We report the case of a 45-year-old woman with no prior medical or gynecologic history who presented with a 1-week history of nausea, vomiting, abdominal pain, and obstipation. Imaging studies revealed terminal ileal lesions, and colonoscopy identified a large obstructive polypoid lesion 4 cm proximal to the ileocecal valve. She underwent laparoscopic ileocolic resection, which revealed an obstructed and perforated terminal ileum. Histopathological analysis demonstrated florid granulation tissue, subserosal fibrosis, and a purulent exudate, with endometriotic inclusions comprising endometrial glands and stroma in the terminal ileum and appendix. The ileal and colonic mucosa were unremarkable, and no reactive lymphadenopathy was found. A final diagnosis of ileal endometriosis was made. Postoperatively, the patient recovered well, required no additional medical therapy, and experienced a significant improvement in symptoms without recurrence. This case highlights an unusual presentation of terminal ileal endometriosis causing small bowel obstruction and perforation, masquerading as Crohn’s disease. The absence of typical gynecologic symptoms or mucosal abnormalities underscores the diagnostic complexity. Recognition of this rare entity is crucial, as timely surgical intervention can be curative and significantly enhance patient outcomes. This case reinforces the importance of maintaining a broad differential diagnosis in women presenting with unexplained gastrointestinal symptoms and ileal lesions.