Table 2.

Clinical features of functional pancreatic neuroendocrine tumors

Tumor	Percentage	Secreted hormone	Malignant	Clinical features	Biochemical evaluation
Insulinoma	40%-60%	Insulin	< 10%	Hypoglycemia	Insulin, pro-insulin, C-peptide, 72 h fasting insulin/glucose ratio
Gastrinoma	20%-50%	Gastrin	60%-90%	PUD, GERD, diarrhea	Fasting gastrin (off PPI), secretin stimulation test
Glucagonoma	Rare	Glucagon	50%-80%	Necrolytic migratory erythema, diabetes, venous thrombosis, depression	Glucagon
Somatostatinoma	Rare	Somatostatin	> 70%	Diabetes, hypochlorhydria, cholelithiasis, diarrhea	Somatostatin (not widely available)
VIPoma	Rare	Vasoactive Intestinal Peptide	40%-70%	Watery diarrhea, hypokalemia, achlorhydria	VIP

PUD: Peptic ulcer disease; GERD: Gastroesophageal reflux disease; PPI: Proton pump inhibitor.