Soft tissue

Peripheral nerve


Neurofibromatosis type 1

Last author update: 1 November 2012
Last staff update: 15 September 2020

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PubMed Search: Neurofibromatosis type 1 [title] soft tissue

Vijay Shankar, M.D.
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Cite this page: Shankar V. Neurofibromatosis type 1. website. Accessed August 14th, 2022.
Definition / general
  • Also called von Recklinghausen disease, NF1
  • Defect in neurofibromin gene at 17q11.2; protein is widely expressed tumor suppressor gene that downregulates p21 ras oncoprotein; highest levels in neural tissue; gene has numerous sites of mutation; variable phenotypic expression
  • 1/3000 individuals, 50% from autosomal dominant inheritance, 50% are new mutations
  • Adrenomedullin (ADM) is serum biomarker of NF1 (Clin Cancer Res 2010;16:5048)
Clinical features
  • Multiple neurofibromas (plexiform, solitary); plexiform are relatively specific
  • 6 or more cafe au lait spots over nerve trunks, 1.5 cm or larger (cafe au lait spot: increase in melanin in epidermal basal layer, may overlie a neurofibroma, smooth delicate margins; solitary cafĂ© au lait spots are normal)
  • Lisch nodules (pigmented iris hamartomas, 94% by age 6)
  • 2 - 4x increased risk of other tumors (childhood CML, ganglioneuroma, meningioma, pheochromocytoma, rhabdomyosarcoma); 5 - 13% develop MPNST; also acoustic neuroma (schwannoma), astrocytoma, gastric carcinoid, GIST, glomus tumor, lipoma, optic nerve glioma, Wilm tumor (Hum Genomics 2011;5:623)
  • Nontumors: congenital malformations, fibrosing alveolitis, megacolon, skeletal lesions (30%-spinal deformities [kyphoscoliosis], bone cysts)
Clinical images

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Cafe au lait spots

Differential diagnosis
  • Albright's syndrome: polyostotic fibrous dysplasia of bone, patchy dermal pigmentation, endocrine dysfunction
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