islet cell tumors Flashcards
What is the most common type of islet cell tumor?
Insulinoma (arising from beta cells).
What genetic syndrome is insulinoma commonly associated with?
MEN I (Multiple Endocrine Neoplasia type I)
What are the key symptoms of insulinoma?
• Neurological: confusion, seizures, altered mental status
• Sympathetic: tremors, tachycardia, anxiety, diaphoresis
What is the Whipple triad for insulinoma diagnosis?
- Symptoms of hypoglycemia
- Low blood glucose (<50 mg/dL)
- Relief of symptoms after eating
What are the key lab findings in insulinoma?
• Low fasting glucose
• High insulin
• High C-peptide (to differentiate from factitious insulin use)
What is the treatment for insulinoma?
Surgical resection (90% curative); diazoxide can be used to inhibit insulin release.
What is the second most common islet cell tumor?
Gastrinoma (Zollinger-Ellison syndrome)
What are the key features of gastrinoma?
• Refractory peptic ulcer disease (PUD)
• Multiple ulcers
• Located in gastrinoma triangle
How is gastrinoma diagnosed?
• Upper endoscopy: multiple ulcers
• Serum gastrin level > 1000 pg/mL
How is gastrinoma managed?
PPI, surgical resection, and chemotherapy
What is VIPoma and what hormone does it secrete?
A tumor that secretes vasoactive intestinal peptide (VIP).
What is the classic triad seen in VIPoma?
- Watery diarrhea
- Hypokalemia
- Achlorhydria
What is the treatment for VIPoma?
Surgical resection, chemotherapy, octreotide for symptom control
What is glucagonoma and what cell type does it arise from?
A tumor from alpha cells that secretes glucagon.
What are key features of glucagonoma?
• Hyperglycemia
• Weight loss
• Necrolytic migratory erythema (psoriatic-like rash on limbs/trunk)
How is glucagonoma diagnosed and treated?
• High fasting glucagon levels, skin biopsy of rash
• Surgical resection, chemotherapy, and octreotide
