NCIt definition : 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);
Alternative definition : NCI-GLOSS: A nerve that has become thick and misshapen due to the abnormal growth
of cells and tissues that cover the nerve.;