Figure 7b. Plexiform neurofibroma of the mesentery in a 10-year-old girl with NF1 who complained of chronic abdominal pain. (a–c) Intravenous contrast-enhanced CT scans show a large, multilobulated hypoattenuating mass arising from the sigmoid mesentery (* in a). There are extensive plexiform neurofibromas involving the lumbosacral plexus (arrows). (d) Image from an air contrast barium enema study shows leftward displacement and scalloping of the medial margin of the sigmoid colon (arrows). (e) Photograph of the cut surface of the resected mesenteric mass shows a lobulated mass composed of numerous mucoid plexiform neurofibromas. Cystic degeneration is also present. The mass partially encircles the sigmoid colon (arrow).