Soft tissue
Peripheral nerve
Neurofibroma - general

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: Neurofibroma [title] soft tissue

Definition / General
  • Benign, common, spindle cell tumor; multiple tumors associated with neurofibromatosis type 1
  • Solitary tumor suggests patient does NOT have neurofibromatosis type 1
  • Malignant transformation rare in sporadic neurofibromas

Subtypes:
  • Plexiform neurofibroma: irregularly expanded nerve bundles with nodular appearance, prominent myxoid matrix; associated with NF1
  • Diffuse cutaneous: traps adnexa, infiltrates into fat
  • Focal cutaneous
  • Intraneural
Case Reports
Clinical Images

Images hosted on PathOut servers:

Cutaneous, courtesy of Mark R. Wick, M.D.



Images hosted on other servers:

Mass of low density

MRI

Large intrascrotal mass

Mouth

Skin

Gross Description
  • Not encapsulated, softer (more gelatinous) than schwannoma
  • Superficial tumors are small, pedunculated nodules protruding from skin (molluscum pendulum)
  • Deeper tumors are larger, may cause tortuous enlargement of peripheral nerves (plexiform neurofibromas)
Gross Images

Images hosted on other servers:

Large inguinal mass

Micro Description
  • Non-encapsulated
  • Proliferation of all elements of peripheral nerves
  • Schwann cells with wire like collagen fibrils (wavy serpentine nuclei, pointed ends), stromal mucosubstances, mast cells, Wagner-Meissner corpuscles, Pacinian corpuscles, axons (highlight with silver or acetylcholinesterase stain, NSE, neurofilament), fibroblasts and collagen
  • Perineurial cells in plexiform types, mitotic figures are rare
  • Less of a fascicular pattern than fibromatosis
  • May be infiltrative, have myxoid areas, contain melanin pigment, have epitheloid morphology
  • Rarely has skeletal differentiation (neuromuscular hamartoma)
  • No Verocay bodies, no nuclear palisading, no hyalinized thickening of vessel walls
Micro Images

Images hosted on PathOut servers:
Images courtesy of Mark R. Wick, M.D.:

Cutaneous diffuse

Cutaneous sclerotic

S100





Images hosted on other servers:

H&E, bundles of spindle cells

H&E

Various images

Various images

Caption unknown

Positive Stains
Negative Stains
  • EMA (except in plexiform neurofibromas)
Electron Microscopy Description
  • Schwann cells enclose axons in plasmalemmal invaginations (mesaxons)
Differential Diagnosis