Pancreatic neuroendocrine tumors (PNETs) constitute 1 to 2% of pancreatic neoplasms and show unique genetics, biology, and prognosis relative to pancreatic adenocarcinomas.They originate from diffuse neuroendocrine cells with two probable origins: mature endocrine cells in the pancreas and multipotent stem cells that can differentiate into endocrine and exocrine cells in the pancreas. PNETs are classified as either functional or non-functional, depending on whether a patient experiences symptoms related to excess hormone (e.g. gastrin, insulin, glucagon, vasoactive intestinal peptide etc.) production by the tumor. Few important ones are discussed here.

Insulinoma

It is the commonest neuroendocrine tumor of the pancreas with an annual incidence of four in every 1 million persons & comprises 70% to 80% of all functional neuroendocrine pancreatic tumors.Clinical symptoms are due to hypoglycaemia and adrenergic activity like sweating, palpitations, weakness, tremors, Visual disturbance or altered mental status etc. Another notable manifestation of Insulinoma is weight gain, as patients may eat frequently to avoid symptoms.Usually these tumours are single and benign, so enucleation is the procedure of choice,
however in syndromic setting, more extensive surgery like distal pancreatectomy, whipple`s procedure may be considered.

Gastrinoma

Gastrinomas are usually located outside the pancreas, with sites in the duodenal wall, stomach, jejunum, peri pancreatic tissue, ovaries, and liver. There is long delay before presentation/diagnosis of these tumours (mean delay around 5years). At least 60% of Gastrinomas are malignant. The principal symptoms remain those due to peptic ulcer disease or severe GERD (abdominal pain, nausea, heartburn, vomiting) with or without diarrhoea. Surgical resection is the mainstay of therapy for patients who present with locoregional disease whereas cytoreductive surgery can be considered in cases of metastatic disease.