Small intestine & ampulla

Other malignancies

Malignant GI neuroectodermal tumor



Topic Completed: 12 January 2021

Minor changes: 12 January 2021

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PubMed Search: "Malignant gastrointestinal neuroectodermal tumor"

Raul S. Gonzalez, M.D.
Page views in 2020: 2,489
Page views in 2021 to date: 3,137
Cite this page: Gonzalez RS. Malignant GI neuroectodermal tumor. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/smallbowelmaliggastroneuroectodermaltumor.html. Accessed December 6th, 2021.
Definition / general
  • Rare malignant mesenchymal neoplasm of the gastrointestinal tract
Essential features
  • Mesenchymal malignancy that grows in sheets or cords and may have osteoclast-like giant cells
  • Positive for S100 and synaptophysin; negative for HMB45 and MelanA
  • Harbors EWSR1 translocation
Terminology
  • Also known as clear cell sarcoma-like tumor of the gastrointestinal tract
Sites
Clinical features
  • Median age 35 years; no sex predilection (Arch Pathol Lab Med 2015;139:407)
  • Most common symptoms are abdominal pain and intestinal obstruction
  • Tumor can spread to lymph nodes and liver and may cause death
Case reports
Treatment
  • Surgery; possible adjuvant role for c-Met / ALK inhibitors and VEGF inhibitors (Oncology 2016;91:348)
Gross description
  • Large mass (mean 5 cm)
Microscopic (histologic) description
  • Sheets or nests of oval / spindled mesenchymal cells with clear or eosinophilic cytoplasm, visible nucleoli and often mitoses
  • Osteoclast-like giant cells may be seen
  • Tumor often spans the entire wall
Microscopic (histologic) images

Contributed by Raul S. Gonzalez, M.D.

Low power

Intermediate power

High power

Positive stains
Negative stains
Electron microscopy description
  • Secretory vesicles and dense core granules
Molecular / cytogenetics description
  • Translocation involving EWSR1 (most commonly EWSR1-ATF1 [t(12;22)] or EWSR1-CREB1)
Sample pathology report
  • Jejunum, resection:
    • Malignant gastrointestinal neuroectodermal tumor (6.1 cm) (see comment)
    • Lymphovascular invasion present.
    • Margins of resection unremarkable.
    • Three of eight lymph nodes involved by metastatic tumor (3/8).
    • Comment: Gastrointestinal neuroectodermal tumor is a rare malignancy that can metastasize distantly and has a poor prognosis. Immunohistochemical stains show the tumor is positive for S100 and synaptophysin.
Differential diagnosis
Additional references
Board review style question #1
Which of the following is true about malignant gastrointestinal neuroectodermal tumor?

  1. It can demonstrate a t(12;22) EWSR1-ATF1 translocation
  2. It most commonly occurs in the colon
  3. Its preferred site of metastasis is the lungs
  4. It stains positive for S100 and cytokeratin by immunohistochemistry
  5. Most patients are in their sixth decade or older
Board review style answer #1
A. It can demonstrate a t(12;22) EWSR1-ATF1 translocation

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Reference: Malignant GI neuroectodermal tumor
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