Neuroendocrine neoplasms

Neuroendocrine tumor with sarcomatous differentiation

Editor-in-Chief: Debra L. Zynger, M.D.
Raul S. Gonzalez, M.D.

Last author update: 11 January 2021
Last staff update: 12 January 2021

Copyright: 2002-2023,, Inc.

PubMed Search: Neuroendocrine tumor with sarcomatous differentiation

Raul S. Gonzalez, M.D.
Page views in 2022: 556
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Cite this page: Gonzalez RS. Neuroendocrine tumor with sarcomatous differentiation. website. Accessed January 28th, 2023.
Definition / general
  • Well differentiated neuroendocrine tumor with poorly differentiated myosarcomatous component
Essential features
  • Extremely rare lesion (two cases reported in English literature)
  • Lesion may transition from neuroendocrine to sarcomatous component or may have two discrete admixed components
  • Both reported cases use outdated term islet cell tumor, as they were published in 1989 and 2001
ICD coding
  • ICD-10: C25.4 - malignant neoplasm of endocrine pancreas
Radiology images

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CT scan

Case reports
Microscopic (histologic) description
  • Lesion is primarily composed of typical well differentiated neuroendocrine tumor
  • Sarcomatous component may have rhabdomyosarcomatous features or may show spindled cells with enlarged nuclei arranged in bundles
  • Sarcomatous component is admixed with neuroendocrine component but transition may be gradual or abrupt (with sarcomatous component appearing as discrete nodules)
Microscopic (histologic) images

Images hosted on other servers:

Nests of small, uniform polygonal cells

Pushing margin

Spindle cell component



Topoisomerase II alpha

Positive stains
Electron microscopy description
  • Z lines and thick filaments (if rhabdomyosarcomatous component)
Sample pathology report
  • Pancreas and duodenum, Whipple procedure:
    • Pancreatic neuroendocrine tumor with focal sarcomatous differentiation (see synoptic report and comment)
    • Comment: Sarcomatous differentiation is extremely rare in pancreatic neuroendocrine tumors. Immunohistochemical stains for synaptophysin and chromogranin are positive in the typical neuroendocrine component and the Ki67 index in that component is approximately 2.7% (WHO grade 1).
Differential diagnosis
  • Leiomyosarcoma:
    • Most common sarcoma of pancreas
    • Would not demonstrate neuroendocrine component
Board review style question #1
A neuroendocrine tumor of the pancreas with a sarcomatous component would be most likely to show what sort of differentiation within that component?

  1. Angiosarcomatous
  2. Leiomyosarcomatous
  3. Liposarcomatous
  4. Osteosarcomatous
Board review style answer #1
B. Leiomyosarcomatous. Additionally, leiomyosarcoma is the most common primary sarcoma of the pancreas.

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Reference: Neuroendocrine tumor with sarcomatous differentiation
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