Esophagus
Other malignancies
Malignant peripheral nerve sheath tumor (MPNST)

Author: Feriyl Bhaijee, M.D. (see Authors page)
Editor: Israh Akhtar, M.D.

Revised: 31 January 2018, last major update November 2013

Copyright: (c) 2003-2018, PathologyOutlines.com, Inc.

PubMed Search: Malignant peripheral nerve sheath tumor esophagus

Cite this page: Bhaijee, F. Malignant peripheral nerve sheath tumor (MPNST). PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/esophagusmpnst.html. Accessed December 16th, 2018.
Definition / general
  • Malignant tumor arising from peripheral nerve or a neurofibroma or in extraneural soft tissue and showing nerve sheath differentiation
  • 50 - 65% are associated with neurofibromatosis type 1 (NF1)
    • Plexiform neurofibroma may degenerate into MPNST in NF1 patients
  • Most common locations: buttocks, thigh, brachial plexus, arm, paraspinal region
Terminology
  • Synonym: malignant schwannoma
Epidemiology
  • Extremely rare in esophagus (< 10 reported cases)
  • Sporadic tumors: 2nd - 5th decade
  • NF1 related tumors: 3rd - 6th decade
  • Male predominance
Clinical features
  • Asymptomatic mass or stricture
  • Dysphagia, odynophagia
  • Upper endoscopy: exophytic tumor (Dig Surg 2000;17:627)
Radiology description
  • Difficult to differentiate from benign nerve sheath tumors
  • Features suggestive of malignancy
    • Size > 5 cm
    • Infiltrative borders
    • Necrosis
  • Double contrast barium study: mid esophageal stricture (Dig Surg 2000;17:627)
Prognostic factors
  • Poor prognostic factors
    • NF1 related tumors: high morbidity and mortality
    • High histologic grade
      • Cytologic atypia
      • Brisk mitotic activity (> 5/10 HPFs)
      • Hypercellularity ± necrosis
Case reports
Treatment
  • Complete surgical excision
  • Adjuvant therapy for high grade MPNST
Gross description
  • Fusiform, pseudoencapsulated, tan / gray soft tissue mass with variable hemorrhage and necrosis
  • Usually > 5 cm
Gross images

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Site unspecified: large peripheral nerve trunks

Microscopic (histologic) description
  • Alternating zones of hypo and hypercellularity (marbled appearance)
  • Accentuated perivascular cellularity, often with tumor herniation into blood vessels
  • Long fascicles of spindled or epithelioid cells with wavy / buckled, hyperchromatic nuclei and lightly eosinophilic cytoplasm
  • Heterologous differentiation (skeletal muscle, osteochondroid, glands) in some NF1 related MPNST
    • With rhabdomyoblasts: so called malignant triton tumor
  • Branching staghorn (HPC-like) vasculature may be present
  • Geographic necrosis
  • Epithelioid MPNST: nested pattern, prominent macronucleoli
Microscopic (histologic) images

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Not esophagus:

Herringbone pattern

Abundant mitotic activity


Features of MPNST

Rare MPNST variants

Low grade MPNST

Cytology description
  • Clusters and fascicles of spindled to ovoid cells with high nuclear:cytoplasmic ratios
  • Fibrillary background
Cytology images

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Spindle to oval shaped cells

Positive stains
  • S100 protein:
    • Weak / focal in spindled MPNST
    • Diffuse / strong in epithelioid MPNST
  • Desmin, myogenin, MyoD1: MPNST with rhabdomyoblastic differentiation
  • Cytokeratin: MPNST with glandular differentiation
  • GFAP, CD34: occasionally positive in spindled MPNST
Negative stains
Electron microscopy description
Molecular / cytogenetics description
  • No consistent genetic events reported
  • t(X;18) negative (unlike synovial sarcoma)
  • Frequent pathogenetic events
    • Tumor suppressor gene mutations, e.g. TP53, CDKN2A
    • Receptor tyrosine kinase amplification, e.g. EGFR
Molecular / cytogenetics images

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Low grade MPNST:
EGFR amplification
and homozygous
CDKN2A deletions

Differential diagnosis
  • Cellular neurofibroma: moderate cellularity and fascicular growth pattern but lacks monotonous cytologic atypia, chromatin abnormalities and mitotic activity (as seen in MPNST)
  • Neurofibroma with ancient change (atypical neurofibroma): degenerative cytologic atypia but lacks increased cellularity, fascicular growth and mitotic activity (as seen in MPNST)
  • Cellular schwannoma: diffuse S100+ (Ann Thorac Surg 2011;92:357)
  • Melanoma: melanocytic markers+
  • Monomorphic spindle cell sarcomas
  • Ossifying fibromyxoid tumor: usually bland cytology but a subset may have a spindle cell component
Additional references