A nerve that has become thick and misshapen due to the abnormal growth of cells and tissues that cover the nerve.

A neurofibroma in which Schwann cells proliferate inside the nerve sheath, producing an irregularly thickened, distorted, tortuous structure.

An elongated and multinodular neurofibroma, formed when the tumor involves either multiple trunks of a plexus or multiple fascicles of a large nerve, such as the sciatic. Some plexiform neurofibromas resemble a bag of worms, others produce a massive ropy enlargement of the nerve. (Adapted from WHO)

(neurofibroma, plexiform) A type of neurofibroma manifesting as a diffuse overgrowth of subcutaneous tissue, usually involving the face, scalp, neck, and chest but occasionally occurring in the abdomen or pelvis. The tumors tend to progress, and may extend along nerve roots to eventually involve the spinal roots and spinal cord. This process is almost always a manifestation of NEUROFIBROMATOSIS 1. (From Adams et al., Principles of Neurology, 6th ed, p1016; J Pediatr 1997 Nov;131(5):678-82)