Then the patient lay on the left for another rectal observation, and a subtle surface pattern of the rectal mucosa 8 cm above the anal edge was noticed, which did not disappear after gas injection (Figure 1A). The patient had a discoid resection of the rectal wall showing the muscle layer infiltrated by EM. I Dear Sir i , Three patients were diagnosed with endometriosis (EM) and suspected of colorectal involvement on MRI scan, so they were sent for colonoscopy to define the degree of colorectal involvement (Video S1). [Extracted from the article]