Ans. (c) InsulinomaRef: Sabistons Text book of Surgery 20th Ed; Page No-952Insulinoma* Insulinoma is the most common functioning pancreatic neuroendocrine tumors (PNET).* Incidence rate is very rare: Annually 1-2 per 1 million populations.Clinical Features* Hypoglycemia including fatigue, weakness, fearfulness, hunger, tremor, diaphoresis, and tachycardia accompanied by neurologic manifestations like apathy, irritability, anxiety, confusion, excitement, loss of orientation, blurred vision, delirium, stupor, coma, or seizures* It is curative because mostly benign (85-90%) and solitary.* The gold standard for diagnosis of insulinoma is the 72-hour monitored fast.* C peptide and proinsulin values are elevated.* First localization investigation performed CECT SCAN (2/3rd can be identified) - Hypervascular lesions identified.* Intraop USG is the best investigation to localize.* Preoperatively-EUS has about 90% sensitivity.Treatment* Head of pancreas: Enucleation is the treatment of choice.NoteEnucleation should not be performed if the tumor is within 2mm of the main pancreatic duct.* Distal pancreatectomy, central pancreatectomy, or pancreaticoduodenectomy performed for tumors abutting the main pancreatic duct or for large tumors (Body and tail).* Diazoxide, or streptozotocin plus 5-fluorouracil used for persistent hyperinsulinism after surgery for metastatic islet cell tumors.Sabiston's 20th Ed SaysHot Topic* MC functioning PNET: Insulinoma > Gastrinoma (Second MC).* MC endocrine syndrome seen in patients with MEN1: Gastrinoma (54%)> Insulinoma (21%)> Glucagonoma (3%)>VIPoma (1%).* MC malignant endocrine neoplasm: Gastrinoma >Insulinoma* MC neuroendocrine tumor: Non-functioning tumors