Other malignancies
Ewing sarcoma / primitive neuroectodermal tumor

Topic Completed: 1 August 2013

Minor changes: 12 December 2019

Copyright: 2003-2019,, Inc.

PubMed Search: Ewing sarcoma[TIAB] OR primitive neuroectodermal tumor[TIAB] esophagus

Feriyl Bhaijee, M.D.
Israh Akhtar, M.D.
Page views in 2019: 2,540
Page views in 2020 to date: 1,182
Cite this page: Bhaijee F, Akhtar I. Ewing sarcoma / primitive neuroectodermal tumor. website. Accessed June 3rd, 2020.
Definition / general
  • Highly malignant small round blue cell tumor characterized by recurrent chromosomal translocations [t(11;22) EWSR1-FLI1 or t(21;22) EWSR1-ERG] and membranous MIC2 / CD99 overexpression
  • No known risk factors
  • Ewing family of tumors includes:
    • Ewing sarcoma
    • Primitive neuroectodermal tumor (PNET)
    • Askin tumor (PNET of chest wall)
  • Extremely rare: only 2 reported cases in esophagus (see case reports below)
Clinical features
  • Progressive dysphagia
  • Biopsy with immunohistochemical / molecular confirmation
Case reports
  • Multimodal therapy: chemo / radiotherapy
Gross description
  • Polypoid mass
  • Variable hemorrhage and necrosis
Microscopic (histologic) description
  • Sheets or vague lobules of uniform, round blue cells with clear to eosinophilic cytoplasm, intracytoplasmic glycogen (diastase digestion on PAS stain), fine chromatin, small nucleoli
  • Geographic necrosis and individual degenerating cells common
  • Occasional pseudorosettes, cytoplasmic spindling (features of neuroectodermal differentiation)
  • Rare histologic variants (at all sites, Diagnostic Histopathology 2012;18:348):
    • Adamantinoma-like: nests of epithelioid cells with peripheral palisading and surrounding desmoplasia, high molecular weight cytokeratin+
    • Anaplastic / clear cell
    • Large cell / atypical: large epithelioid cells with pleomorphic nuclei and prominent nucleoli
    • Sclerosing: abundant hyalinized eosinophilic matrix
    • Spindle cell sarcoma-like
    • Vascular-like: hemangioendothelioma-like features
Microscopic (histologic) images

Images hosted on other servers:

Site unspecified

Cytology description
  • Dimorphic population: blastemic (light) and lymphocyte-like (dark) cells
    • Blastemic cells have fine chromatin and distinct nucleoli
    • Lymphocyte-like cells have dense chromatin and inconspicuous nucleoli
  • Coarse cytoplasmic vacuoles, may contain glycogen
  • Variable tigroid background
Cytology images

Images hosted on other servers:

Pleomorphic round cells (not esophagus)

Positive stains
Electron microscopy description
  • Extensive cytoplasmic glycogen deposits
Electron microscopy images

Images hosted on other servers:

Ewing sarcoma of bone

Molecular / cytogenetics description
  • RT-PCR or FISH: recurrent chromosomal translocations resulting in the exchange of N terminal portions between EWS (on 22q) and the EST family transcription factors, FLI1 (on 11q) or ERG (on 21q)
    • t(11;22)(q24;q12) - EWS-FLI1 fusion transcript (> 90%)
    • t(21;22)(q22;q12) - EWS-ERG fusion transcript (5%)
    • t(7;22) EWS-ETV1, t(17;22) EWS-E1AF, t(2;22) EWS-FEV (< 1%)
Molecular / cytogenetics images

Images hosted on other servers:

EWSR1 gene

Differential diagnosis
Back to top