Soft tissue
Peripheral nerve
Neurofibromatosis type 1

Author: Vijay Shankar, M.D. (see Authors page)

Revised: 19 September 2016, last major update November 2012

Copyright: (c) 2002-2016, PathologyOutlines.com, Inc.

PubMed Search: Neurofibromatosis type 1 [title] soft tissue

Cite this page: Neurofibromatosis type 1. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/softtissueNF1.html. Accessed December 10th, 2016.
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

Images hosted on other servers:

Cafe au lait spots

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