Mesenteric plexiform neurofibroma in an 11-year-old boy with von Recklinghausen disease.

We experienced the case of an 11-year-old boy diagnosed as having type 1 neurofibromatosis with intraabdominal and pelvic masses. On physical examination, there were multiple café-au-lait spots larger than 15 mm in diameter scattered over the patient's entire body and axillary freckling, but no cutaneous neurofibromas were present. Lisch nodules were detected in the iris by a slit lamp. A large, firm mobile mass was palpated in the lower abdomen. Abdominal computed tomographic scan showed the hypodense masses in the lower abdomen and pelvic cavity. At laparotomy, a 16 x 9-cm, firm nodular mass along the mesentery of the terminal ileum and ascending colon was found. The mesenteric mass was encasing the superior mesenteric vessels and extending into the serosa of the intestine. The mass was incompletely excised together with affected intestine. However, resection of the rectum could not be performed because of the extensive involvement of the entire mesorectum. Histopathologic study revealed a plexiform neurofibroma involving the mesentery and intestine without evidence of malignant transformation. The postoperative course was uneventful. Ten months after the operation, a magnetic resonance imaging showed no interval change of the mesorectal mass.