Neuroendocrine tumour of the pancreas

Neuroendocrine tumour of the pancreas, also pancreatic neuroendocrine tumour, is a relatively uncommon tumour.

It may be abbreviated PanNET.

Previously, it was referred to as pancreatic islet cell tumour or islet cell tumour; this term is now considered to be outdated.

General

• Rare.
• Presentation depends on subtype, e.g. for insulinoma the typical presentation is hypoglycemia.
• May be part of a syndrome:
  • Multiple endocrine neoplasia I.
  • Von Hippel-Lindau disease.
  • Neurofibromatosis type 1.

Classification

Based on peptide produced in the pancreatic islets:

1. Glucagon from alpha cells (glucagonoma).
2. Insulin from beta cells (insulinoma) - most common ~ 50% of islet cell tumours.
3. Somatostatin from D cells (somatostatinoma).
4. Pancreatic polypeptide from PP cells.

Others:

1. Vasoactive intestinal peptide (VIPoma).
2. Gastrin (gastrinoma).
   • May be seen in Zollinger-Ellison syndrome.
     • Triad: pancreatic gastrinoma, gastric acid hypersecretion, marked peptic ulcers in the small bowel.

Gross

• Usually in the head of the pancreas - 68% in one series, and 50% in another series.

Microscopic

Features:

• Nests of cells.
• Stippled chromatin.
• +/-Hyaline globules.

DDx:

• Solid pseudopapillary neoplasm.
• Acinar cell carcinoma.

Images

www:

• Islet cell tumour (upmc.edu).
• Pancreatic NET with features of SPT (upmc.edu).
• Pancreatic NET - another case (upmc.edu).

IHC

• CK19 +ve -- should be done as a routine in pancreatic NETs; poor prognostic factor.

Note:

• CK19 should not be confused with CA19-9.

See also

• Pancreas.