Ulcerated polypoidal lesion in rectum: not always a malignancy

A 16-year-old boy presented with a history of painless, fresh bleeding from the rectum and a prolapsing mass during defecation for the previous 6 months. On digital rectal examination, multiple polyps were felt. A full colonoscopy revealed a large (2 cm) multilobulated polypoidal growth with an ulcerated surface just above the dentate line covering >50% of the lumen (A). Contrast-enhanced CT showed an eccentric, asymmetrical polypoidal lesion with enhancing wall thickening in the rectum, without any locoregional or distant lymph node involvement (B). Histopathologic examination showed cysts lined by atrophic colonic mucinous epithelium with abundant extravasated mucin in the submucosa without any dysplasia (C, H&E, orig. mag. X400). Serum carcinoembryonic antigen was normal. The findings were consistent with a diagnosis of colitis cystica profunda (CCP). The boy was given hydrocortisone enemas and instructed to perform pelvic floor exercises for 3 months. Although he was clinically asymptomatic, proctosigmoidoscopy at 3 months showed partial resolution (D, left). Hence, therapy was extended for another month, and repeated proctosigmoidoscopy at 1 year showed complete resolution (D, right).