Neuroendocrine neoplasms
Neuroendocrine tumor with sarcomatous differentiation

Topic Completed: 17 January 2019

Minor changes: 24 July 2020

Copyright: 2002-2020,, Inc.

PubMed Search: Neuroendocrine tumor with sarcomatous differentiation

Raul S. Gonzalez, M.D.
Page views in 2019: 262
Page views in 2020 to date: 272
Cite this page: Gonzalez RS. Neuroendocrine tumor with sarcomatous differentiation. website. Accessed November 27th, 2020.
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  • Both reported cases use outdated term islet cell tumor, as they were published in 1989 and 2001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

Images hosted on other servers:

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)
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 answer #1
B. Leiomyosarcomatous. Additionally, leiomyosarcoma is the most common primary sarcoma of the pancreas.

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