Neuroendocrine neoplasms


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

Topic Completed: 10 December 2020

Minor changes: 8 April 2021

Copyright: 2002-2021,, Inc.

PubMed Search: Somatostatinoma[TI] pancreas

Raul S. Gonzalez, M.D.
Page views in 2020: 941
Page views in 2021 to date: 886
Cite this page: Gonzalez R. Somatostatinoma. website. Accessed October 16th, 2021.
Definition / general
  • Neuroendocrine neoplasm (may be well differentiated tumor or poorly differentiated carcinoma) that secretes somatostatin, leading to diabetes, cholecystolithiasis, steatorrhea and diarrhea (J Hepatobiliary Pancreat Sci 2015;22:578)
Essential features
  • Rare functional neuroendocrine neoplasm that secretes somatostatin
  • May appear microscopically as a well differentiated tumor or a poorly differentiated carcinoma
  • Also called delta cell tumor
ICD coding
  • C7A.8 - other malignant neuroendocrine tumors
  • E16.8 - other specified disorders of pancreatic internal secretion
  • Can occur in the pancreas or in the ampulla / duodenum
Clinical features
  • Rare; may be more common in women
  • May occur in patients with NF1 (Clin Gastroenterol Hepatol 2009;7:A28)
  • Most lesions that stain for somatostatin by immunohistochemistry do not produce somatostatinoma syndrome and arguably do not qualify to be diagnosed as somatostatinomas (Endocr Relat Cancer 2008;15:229)
  • Often metastasizes but still usually has good prognosis
  • Imaging to detect pancreatic mass
  • Elevated plasma somatostatin levels
Radiology images

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CT pancreas mass

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PET with metastases

Case reports
  • Surgical resection of primary lesion, if possible
  • Hepatic metastases can be resected or embolized
  • Octreotide for metastatic disease
Gross images

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Pancreatic and duodenal tumors

Microscopic (histologic) description
  • Some cases are well differentiated neuroendocrine tumor, with nests of monotonous low grade neuroendocrine cells with salt and pepper nuclei and ample amphophilic cytoplasm
  • Other cases are poorly differentiated neuroendocrine carcinoma, with nests and sheets of mildly / moderately pleomorphic cells with high mitotic rate, small cell or large cell features (no salt and pepper nuclei) and foci of necrosis
  • May rarely feature psammoma bodies (which are common in duodenal somatostatinomas) (J Surg Oncol 1995;59:67)
Microscopic (histologic) images

Contributed by Raul S. Gonzalez, M.D.
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Nests and cords of cells

Positive stains
Electron microscopy description
Electron microscopy images

AFIP image

D cell granules

Sample pathology report
  • Pancreas and duodenum, Whipple procedure:
    • Well differentiated neuroendocrine tumor of pancreas (see comment and synoptic report)
    • Comment: Based on the patient’s clinical symptoms, this neuroendocrine tumor is best considered a somatostatinoma.
Differential diagnosis
  • Non gastrin secreting pancreatic neuroendocrine tumor or carcinoma: no histopathologic differences; must be determined on clinical grounds
Board review style question #1
    Patients with a somatostatinoma of the pancreas may experience which symptoms?

  1. Cholelithiasis and steatorrhea
  2. High volume watery diarrhea
  3. Hypoglycemia
  4. Nausea, vomiting and peptic ulcer disease
  5. Necrolytic migratory erythema
Board review style answer #1
A. Cholelithiasis and steatorrhea

Comment Here

Reference: Somatostatinoma
Board review style question #2
    Which of the following is true of pancreatic somatostatinomas?

  1. They are common in patients with von Hippel-Lindau syndrome
  2. They are the most common functional pancreatic neuroendocrine neoplasm
  3. They are typically localized and rarely metastasize
  4. They may be neuroendocrine tumors or carcinomas
  5. They usually contain psammoma bodies
Board review style answer #2
D. They may be neuroendocrine tumors or carcinomas

Comment Here

Reference: Somatostatinoma
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