Soft tissue
Peripheral nerve
Malignant peripheral nerve sheath tumor (MPNST)

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

Revised: 16 October 2016, last major update November 2012

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

PubMed Search: Malignant peripheral nerve sheath tumor [title]

See also: epithelioid, malignant triton

Cite this page: Malignant peripheral nerve sheath tumor (MPNST). website. Accessed October 23rd, 2017.
Definition / general
  • Also known as malignant schwannoma
  • Bulky deep-seated tumor usually arising from major nerves in neck, forearm, lower leg, buttock
  • 50% associated with neurofibromatosis (NF), 50% arise de novo
  • May be due to radiation; rarely arise from ganglioneuroma
  • Usually adults
  • High clinical suspicion for MPNST if NF1 patient or tumor arising within anatomic component of a major nerve or contiguous with neurofibroma
  • Recur locally, distant metastases frequent
  • Plexiform variant in children has better prognosis, otherwise cannot predict prognosis
Case reports
Clinical images

Images hosted on other servers:

Greater omentum

Gross description
  • Large mass producing fusiform enlargement of major nerve (often sciatic)
Gross images

Images hosted on PathOut servers:

Courtesy of Mark R. Wick, M.D.

Images hosted on other servers:

Various images

Firm, grey-white

Microscopic (histologic) description
  • Monomorphic serpentine cells, palisading, large gaping vascular spaces, perivascular plump tumor cells, geographic necrosis with tumor palisading at edges, resembling glioblastoma multiforme
  • Frequent mitotic figures
  • May have bizarre cells
  • 15% have metaplastic cartilage, bone, muscle
  • May have glandular differentiation (positive for keratin, EMA, CEA, chromogranin); if so, presume malignant
  • May have melanin in tumor cells, particularly if arise from spinal nerve roots (overlaps with primary melanoma of nerves)
  • Note: some have no discernable Schwannian features at any level
Microscopic (histologic) images

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



Chondroid differentiation


Melanotic pigmented


Storiform growth

Synovial sarcoma

Images hosted on other servers:

Various images

Epithelioid cells


Various stains

Positive stains
Negative stains
Electron microscopy description
  • Infoldings of cell membrane with lamellar configuration, discontinuous basal lamina, conspicuous intercellular junctions, occasional dense-core granules
Molecular / cytogenetics description
Differential diagnosis