Neurofibromatosis type 1, also known as von Recklinghausen disease, is an autosomal dominant disorder with an incidence of 1 per 4000. Neurofibromas are benign, heterogeneous tumors arising from the connective tissue of peripheral nerve sheaths, especially the endoneurium. Visceral involvement in disseminated neurofibromatosis is rare. Neurofibroma occurs most frequently in the stomach and jejunum, but the colon and anorectal canal may also be involved. Gastrointestinal neurofibromas may lead to bleeding, obstruction, intussusception, protein-losing enteropathy and bowel perforation. We present a case of diffuse involvement of the anorectal area by a huge neurofibroma, with pelvic pain, watery diarrhea and urgency.