Authors: Eun Jeong Bae , Chieh Chiu , Caroline E. Lee

Abstract

Background: Endometriosis affects approximately 10% of reproductive-age females worldwide, yet time to diagnosis remains substantially delayed due to the nonspecific nature of its clinical presentation. Deep endometriosis involving the bowel is uncommon, and terminal ileal involvement is particularly rare. The gold standard for diagnosis remains laparoscopy with histopathological confirmation. Patients with small bowel endometriosis are frequently misdiagnosed with other chronic pain conditions before endometriosis is considered.

Case presentation: A 27-year-old female presented with chronic pelvic pain, dysmenorrhea and cyclical gastrointestinal symptoms. Transvaginal ultrasound demonstrated a superficial rectosigmoid nodule. Subsequent laparoscopy identified stage III endometriosis involving multiple pelvic sites and an unexpected deep endometriotic nodule of the terminal ileum. Segmental ileal resection later confirmed full-thickness bowel involvement causing partial luminal narrowing. Following the bowel resection, the patient reported improvement in pelvic pain and resolution of nausea and vomiting.

Conclusion: Small bowel endometriosis is a rare condition that is challenging to diagnose. This case highlights the limitations of imaging modalities and the importance of maintaining clinical suspicion for endometriosis in females presenting with nonspecific gastrointestinal symptoms, even in the setting of non-diagnostic imaging. Multidisciplinary collaboration and greater reliance on integrated clinical assessment are essential to reduce diagnostic delays and improve patient outcomes.

Keywords: Endometriosis, surgery, chronic pelvic pain, small bowel, case report.