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Plexiform neurofibroma in Adult
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Plexiform neurofibroma in Adult

Contributors: Jason E. Hawkes MD, Amanda Truong BS, Martin Agyei MD, Jamie L. Woodcock MD, Bethany K. H. Lewis MD, MPH, Douglas L. Powell MD, Whitney A. High MD, JD, MEng
Other Resources UpToDate PubMed


Plexiform neurofibromas (PNF) are benign tumors arising from cells of the nerve sheath. Such tumors grow along the length of the nerve, often involving multiple branches. PNF are likely congenital in origin but do not become clinically apparent for several years, typically between ages 3-5 years, although onset after birth and in adulthood have been described. Solitary lesions may be the result of NF1 gene mosaicism or loss of heterozygosity.

PNF are associated with neurofibromatosis type I (NF1) and are considered pathognomonic for this condition. A single plexiform neurofibroma is a single criterion for NF1 (at least two of seven criteria are required for diagnosis). About one-fourth of children with NF1 develop PNF. Facial PNF usually appear within the first 3 years of life and often involve the trigeminal nerve.

Unlike cutaneous and subcutaneous neurofibromas, PNF are unaffected by hormonal changes during puberty or pregnancy. PNF may be asymptomatic but may also cause morbidity because of a propensity to infiltrate surrounding tissue. Complications arise from compression of surrounding structures, which can induce pain, neurologic impairment, motor dysfunction, and cause disfigurement. Rarely PNF can result in death from such complications. PNF carry an approximate 10% risk of developing into malignant peripheral nerve sheath tumors.


D36.10 – Benign neoplasm of peripheral nerves and autonomic nervous system, unspecified

403818001 – Plexiform neurofibroma

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Differential Diagnosis & Pitfalls

  • Congenital or giant melanocytic nevi – Hyperpigmented smooth or verrucous macules, papules, or plaques
  • Becker nevus – Large, hyperpigmented, solitary patches with hypertrichosis commonly on the shoulder or trunk of men
  • Congenital smooth muscle hamartoma – Skin-colored or hyperpigmented plaque often with increased villous or terminal hairs
  • Klippel-Trenaunay-Weber syndrome – Three characteristic features include port-wine stain, abnormal overgrowth of soft tissue and bone, and venous malformations
  • Proteus syndrome (Wiedemann syndrome) – Presents with multiple tumors throughout the body, increasing with age
  • Lipomatosis / lipoma – Well-circumscribed tumors with little to no surface changes or associated symptoms
  • Neurofibroma – Firm or semi-firm papules or nodules that may invaginate or exhibit the "button hole" sign following palpation or compression from above the lesion

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Last Updated:01/04/2017
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Plexiform neurofibroma in Adult
A medical illustration showing key findings of Plexiform neurofibroma : Arm, Head/neck, Leg, Neck, Trunk, Tumor, Inguinal region, Smooth nodules
Clinical image of Plexiform neurofibroma - imageId=2423515. Click to open in gallery.  caption: 'A smooth dark brown nodule on the arm.'
A smooth dark brown nodule on the arm.
Copyright © 2023 VisualDx®. All rights reserved.