Whole-body magnetic resonance images of a 5-year-old boy with neurofibromatosis type 1. There are extensive plexiform neurofibromas involving the thoracic paravertebral regions, intercostal spaces, anterolateral chest wall, retrocrural space, and upper abdominal retroperitoneum. The aorta and its branches (celiac trunk and superior mesenteric artery), left renal vein, and intrahepatic portal vein are encased by the plexiform (arrows). Thoracic scoliosis with right-sided convexity is noted.