Diffuse, retroperitoneal mesenteric and intrahepatic periportal plexiform neurofibroma in a 5-year-old boy.

We present a case of plexiform neurofibroma involving the retroperitoneum, mesentery, and liver in a 5-year-old boy who underwent evaluation for extent of a palpable left neck mass. The mass had intrathoracic extension with great vessel encasement and extension into the abdomen. Abdominal CT revealed a diffuse low-attenuation non-enhancing mass encasing the retroperitoneal vessels with serpiginous extension into the liver along the portal vein. This spread pattern of plexiform neurofibroma is an unusual manifestation of neurofibromatosis in a young child.