Preoperative Diagnosis of Intestinal Endometriosis by Magnifying Colonoscopy and Target Biopsy

Endometriosis can affect any portion of the gastrointestinal tract. A preoperative definitive diagnosis of intestinal endometriosis is difficult, because there is no characteristic endoscopic finding and the endoscopic biopsies usually sample insufficient endometrial tissue for pathologic diagnosis. To our knowledge, the magnifying endoscopic features of intestinal mucosal endometriosis have not been well documented. In this study, we report a case of intestinal endometriosis diagnosed preoperatively by magnifying image-enhanced colonoscopy and target biopsy. A 45-year-old woman was referred to our hospital with abdominal pain in the left lower quadrant. Colonoscopy showed a submucosal tumor-like lesion of approximately 30 mm in diameter exhibiting surface reddening and granular changes in the sigmoid colon. Magnifying endoscopy revealed sparsely distributed round pits in the granules. The mucosal biopsy specimen from the granule provided the diagnosis of intestinal endometriosis. Segmental sigmoidectomy was performed, and pathological examination revealed that the surface colonic mucosa was partially replaced by endometrial tissue, which accounted for the granular change detected in the colonoscopy. It can be speculated that the round pit might reflect the endometrial glands surrounded by endometrial stroma. This case illustrated the characteristic finding and utility of magnifying endoscopy for mucosal intestinal endometriosis.