Pancreas
Neuroendocrine neoplasms
Gastrinoma (G cell tumor)

Author: Deepali Jain, M.D. (see Authors page)

Revised: 22 December 2017, last major update August 2012

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed Search: Gastrinoma[TI] OR G cell tumor[TI] pancreas

Cite this page: Jain, D. Gastrinoma (G cell tumor). PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/pancreasgastrinoma.html. Accessed February 19th, 2018.
Definition / general
  • Functionally active and usually malignant endocrine tumor with clinical symptoms due to inappropriate secretion of gastrin (Zollinger-Ellison syndrome; ZES); either sporadic nonfamilial with ZES (80% of cases) or familial with ZES in the setting of MEN1 (20%) (IARC: 8153 / 3 Gastrinoma, Malignant [Accessed 22 December 2017])
Clinical features
  • Associated with hypersecretion of gastric acid and severe peptic ulceration
  • 90% have ulcers; 85% in duodenum / jejunum, 15% in stomach
  • 50% have diarrhea
  • Tumors usually in pancreas or duodenum (eMedicine: Gastrinoma [Accessed 22 December 2017]), peripancreatic soft tissue, gastric antrum (opposite of G cell distribution)
  • Also ovary, mesentery, liver, intra-abdominal lymph nodes (unclear if due to ectopic pancreatic tissue or metastases)
  • 50% are locally invasive or metastatic at diagnosis
  • Zollinger-Ellison syndrome tumors are usually solitary, malignant, located in pancreas
  • MEN1 cases are less likely to be malignant, arise in duodenal wall, often multicentric
Diagnosis
Primary lymph node gastrinoma
  • Gastrin producing tumors in lymph nodes, with no GI or pancreatic primary
  • Occur with MEN1 (Am J Surg Pathol 2008;32:1101)
  • Occur in gastrinoma triangle: from cystic and common bile ducts to the second and third portion of the duodenum to neck and body of the pancreas
  • Apparently due to gastric secreting neuroendocrine cells within these nodes (Arch Pathol Lab Med 2000;124:832)
  • Also due to occult duodenal microgastrinomas with lymph node metastasis (Am J Surg Pathol 2008;32:1101)
Treatment
  • H2 blockers; surgical resection of tumor (if cannot resect, some advocate total gastrectomy)
Gross images

Images hosted on PathOut server:

AFIP images:

Lymph node: largest (2.5 cm) of 5 pancreatoduodenal lymph nodes with endocrine tumor tissue

Microscopic (histologic) description
  • Nonneoplastic pancreas shows large islets and nesidioblastosis
  • Malignant tumors are histologically bland
  • Associated with pancreatic polypeptide cell hyperplasia (Hum Pathol 1997;28:149)
Microscopic (histologic) images

Images hosted on PathOut server:

AFIP images:

Malignant tumor has trabecular pattern

Lobular trabecular pattern

Duodenum: tumor cells infiltrate Brunner glands

Duodenum: gastrinoma in MEN1 patient arises in deep crypts of mucosa and invades submucosa deeply (immunofluorescence)

Electron microscopy description
  • Granules similar to VIP, normal gastrin producing cells: small, electron dense
Electron microscopy images

Images hosted on PathOut server:

AFIP images:

Pancreatic gastrinoma