Plexiform neurofibromas are among the most common and debilitating complications of neurofibromatosis type 1 (NF1). They account for substantial morbidity, including disfigurement, functional impairment, and may even be life threatening. Plexiform neurofibromas are also subject to transformation into malignant peripheral nerve sheath tumor (MPNST), a complication that is refractory to treatment both because of a paucity of effective therapies for malignant soft tissue sarcomas in general, and because of the delay in diagnosis that results from change of a small portion of a large pre‐existing tumor. The current mainstay of treatment of plexiform neurofibromas, and of MPNST for that matter, is surgical resection. The major variables are the timing and means of identification of plexiform neurofibromas, methods of follow‐up, and indications for surgery. There is no established means of medical treatment, but research into the molecular pathogenesis of NF1, as well as advances in tumor therapy in general, are opening the way towards clinical trials for plexiform neurofibroma. Am. J. Med. Genet. (Semin. Med. Genet.) 89:31–37, 1999. © 1999 Wiley‐Liss, Inc.