Insulinoma vs Other functional pancreatic neuroendocrine tumors
How to tell Insulinoma and Other functional pancreatic neuroendocrine tumors apart when a board question makes them look alike.
Insulinoma: fasting hypoglycemia with high insulin and C-peptide; other pancreatic neuroendocrine tumors are named by their hormone syndrome.
Side by side
Fasting hypoglycemia with high insulin, high C-peptide, neuroglycopenic symptoms, and relief after glucose.
Other pancreatic endocrine tumors produce syndrome-specific hormone excess: gastrin ulcers, VIP watery diarrhea, glucagon rash/diabetes, or somatostatin diabetes/gallstones/steatorrhea.
Autonomous beta-cell insulin secretion drives glucose into tissues and suppresses hepatic glucose output.
Non-beta islet tumors secrete peptide hormones that alter acid secretion, intestinal water/electrolytes, glucose metabolism, or digestive inhibition.
Low glucose with inappropriately high insulin and C-peptide supports insulinoma.
High gastrin, VIP, glucagon, or somatostatin with the matching syndrome supports another functional NET.
The trap
All are pancreatic neuroendocrine tumors, so the hormone effect matters more than the word pancreatic.
The repair move
For pancreatic endocrine tumors, identify the hormone syndrome before naming the tumor.
Try a free question
CoreA patient has recurrent fasting confusion, diaphoresis, low plasma glucose, high insulin, high C-peptide, and symptoms relieved by glucose. Which pancreatic endocrine tumor is most likely?
Show answer and explanation
Answer: A. Insulinoma. Insulinoma causes endogenous hyperinsulinemic hypoglycemia, so insulin and C-peptide are both high.
Why the other choices are tempting
- B. Gastrinoma causes acid hypersecretion, refractory ulcers, and diarrhea.
- C. VIPoma causes watery diarrhea, hypokalemia, and achlorhydria.
- D. Glucagonoma causes diabetes, weight loss, and necrolytic migratory erythema.
- E. Somatostatinoma causes diabetes, gallstones, and steatorrhea.
Flashcards
Tap a card to flip it.
What biochemical pattern favors insulinoma?
Low glucose with high insulin and high C-peptide supports endogenous insulin excess.
What syndrome points to gastrinoma?
Refractory or multiple peptic ulcers with diarrhea from acid hypersecretion points to gastrinoma.
Quick answers
What is the fastest way to tell Insulinoma from Other functional pancreatic neuroendocrine tumors?
Insulinoma: fasting hypoglycemia with high insulin and C-peptide; other pancreatic neuroendocrine tumors are named by their hormone syndrome.
What is the key clue for Insulinoma?
Fasting hypoglycemia with high insulin, high C-peptide, neuroglycopenic symptoms, and relief after glucose.
What is the key clue for Other functional pancreatic neuroendocrine tumors?
Other pancreatic endocrine tumors produce syndrome-specific hormone excess: gastrin ulcers, VIP watery diarrhea, glucagon rash/diabetes, or somatostatin diabetes/gallstones/steatorrhea.
What is the common trap with Insulinoma vs Other functional pancreatic neuroendocrine tumors?
All are pancreatic neuroendocrine tumors, so the hormone effect matters more than the word pancreatic.