Small bowel endometriosis masquerading as regional enteritis

Summary A 35-year-old female presented with recurrent right lower quadrant pain, nausea, and vomiting. She was afebrile with diffuse abdominal tenderness. Plain x-ray of abdomen revealed small bowel obstruction. A barium x-ray of the small bowel showed stricture of the terminal ileum. A CT scan of the abdomen showed a 6-cm mass in right lower quadrant. She was empirically managed as having Crohn's disease. She underwent laparotomy after failure of medical management with high-dose steroids. There was ulceration and narrowing of terminal ileum. Frozen sections revealed endometriosis. Ileocecectomy was performed. Histopathology of resected specimen confirmed the diagnosis of endometriosis, and there was no evidence of chronic inflammatory bowel disease or neoplasia. Ileal endometriosis should be considered in the differential diagnosis of Crohn's disease in menstruating females presenting with perimenstrual symptoms.