Pancreatic endocrine tumors (PETs) are rare neoplasms that arise from the hormone-secreting cells of the pancreas. They can be classified as either functional (hormone-secreting) or non-functional (non-hormone-secreting). The symptoms depend on the type of hormone produced and the size or location of the tumor.

1. Insulin-secreting tumors (Insulinomas)
   • Episodes of hypoglycemia (low blood sugar), especially during fasting or after exercise
   • Symptoms include sweating, palpitations, tremors, confusion, blurred vision, and loss of consciousness
   • Relief of symptoms after glucose intake is typical
2. Gastrin-secreting tumors (Gastrinomas)
   • Recurrent peptic ulcers, often multiple or refractory to treatment
   • Abdominal pain, heartburn, nausea, and vomiting
   • Diarrhea due to excess acid production
3. Glucagon-secreting tumors (Glucagonomas)
   • Skin rash (necrolytic migratory erythema), especially on the face, abdomen, and limbs
   • Weight loss, anemia, diabetes mellitus, and deep vein thrombosis
4. VIP-secreting tumors (VIPomas)
   • Profuse watery diarrhea leading to dehydration and electrolyte imbalance
   • Flushing, low blood potassium, and metabolic acidosis
5. Somatostatin-secreting tumors (Somatostatinomas)
   • Diabetes mellitus, gallstones, diarrhea, and steatorrhea
   • Weight loss and abdominal pain
6. Non-functional tumors
   • Often asymptomatic in early stages
   • Symptoms appear when the tumor grows large enough to compress nearby organs
   • These may include abdominal pain, weight loss, jaundice, nausea, or a palpable mass
7. General tumor-related symptoms
   • Fatigue, loss of appetite, unexplained weight loss, and low-grade fever