The myth of rectovaginal septum endometriosis

Lay summary: Endometriosis is a chronic condition where tissue resembling the uterine lining grows elsewhere in the pelvis, often causing pain, infertility, and inflammation. For decades, textbooks and research papers have described the rectovaginal septum (RVS), the thin layer between the vagina and rectum, as a common site of deep endometriosis. Yet this belief has never been conclusively proven. In our study of 161 patients, combining advanced ultrasound, meticulous keyhole surgery, and tissue analysis, we found no evidence of endometriosis within the RVS. Instead, all lesions were located in surrounding structures, including the uterosacral ligaments, the rectouterine pouch, or the bowel. These findings challenge a long-standing anatomical misconception and call for the retirement of outdated terminology. Clarifying where endometriosis truly occurs is critical for improving diagnosis, surgery, and communication in women's health. Our study overturns decades of dogma by showing that 'rectovaginal septum endometriosis' may be a myth.