A 67-year-old man with von Recklinghausen disease (VRD) was found to have an ill-defined large mass in the ileocecal area on abdominal computed tomography when he was examined for abdominal pain in the right lower quadrant. Because of high serum C-reactive protein level and leukocytosis appendiceal tumor complicated by appendicitis was diagnosed. Due to the possibility of malignancy, standard cancer surgery was carried out to remove the mass, i.e., ileocecal resection together with dissection of the regional lymph nodes. The cecum was displaced by a remarkably enlarged appendix with a firm and thickened wall. The distal portion of the appendix was cystically dilated, forming an abscess. The pathological diagnosis was neurofibromatosis with mucus hyperplasia and abscess formation in the appendix. Neurofibroma of the appendix is very rare, even in patients with VRD. Although it is benign, prompt resection is recommended because of a high risk of appendicitis and malignant transformation.