Figure 14b. Diffuse abdominal and retroperitoneal plexiform neurofibromatosis in an 11-year-old boy who complained of increasing abdominal girth. Intravenous contrast-enhanced CT scans (a obtained at a higher level than b) show low-attenuation plexiform neurofibromas infiltrating throughout the hepatic hilum, paraaortic regions, small bowel mesentery, greater omentum, and retrocrural space.