Video 1 Endoscopic submucosal dissection of colitis cystica profunda in the lower rectum along with resection of the tumor using the pocket-creation and clip-with-line methods. ▶ Fig. 3 The resected specimen. a Photograph of the resected specimen, approximately 9 × 6 cm in size. b Macroscopic view of the resected specimen, showing several cystic lesions containing mucin. c Histological images of the resected specimen stained with hematoxylin and eosin, showing colitis cystica profunda without findings of dysplasia or malignancy (× 12.5).