INTRODUCTION
Submucosal cysts in the colon was first reported by Stark in 1766 during the autopsy of two specimens of patients with chronic dysentery. In 1863, Virchow named it colitis cystica polyposa for multiple polypoid cystic submucosal lesions. In 1957, Goodall and Sinclair renamed colitis cystica polyposa to colitis cystica profunda (CCP), giving the name and detailed description of the disease firstly [1, 2]. CCP is a rare benign disease occurring in the rectum or colon, most commonly in the anterior wall of the rectum. The main pathological characteristics of CCP are mucus-containing cysts reaching deep into the submucosa, muscular layer or even the serous layer. The cysts are filled with large amounts of mucus, and floating exfoliated epithelial cells visible in the mucus, without the characteristics of malignant tumors[3]. There are few case reports concerning endorectal ultrasonography of CCP in previous literatures. We report two cases of CCP with the purpose of better awareness of its clinical and imaging features.