vasoactive-intestinal-peptide and Somatostatinoma

Pancreatic neuroendocrine tumors (PNETs) are rare neoplasms representing <5% of all pancreatic malignancies with an estimated incidence of 1-1.5 cases/100,000. PNETs are broadly classified as either functional or nonfunctional. Functional PNETs include insulinomas, gastrinomas, vasoactive intestinal peptideomas, glucagonomas, and somatostatinomas. The clinical manifestations associated with these tumors are the result of excessive hormonal secretion and action. The functional nature of these tumors makes pancreatic hormone testing critical not only for initial diagnosis but also for follow-up, because they are important tumor markers. Nonfunctional PNETs typically remain clinically silent until a substantial mass effect occurs. Although the majority of PNETs occur sporadically, it is important to recognize that these tumors may be associated with a variety of familial syndromes and in many cases genetic testing of PNET patients is warranted. This article familiarizes the reader with the clinical presentation and the biochemical, radiologic, and genetic testing indicated for diagnosis and follow-up of patients with PNET.

Topics: Gastrinoma; Gastrins; Glucagon; Glucagonoma; Hormones; Humans; Hypoglycemia; Insulinoma; Neuroendocrine Tumors; Pancreatic Neoplasms; Somatostatinoma; Vasoactive Intestinal Peptide; Vipoma

Gut peptide secreting tumours originate most commonly from the pancreatic Islets of Langerhans. Tumours at a variety of other sites have also been shown to synthesize and release these peptides, reflecting the wide distribution of the peptide secreting cells of the diffuse neuroendocrine system. Tumours such as the glucagonomas, insulinomas, VIPomas and gastrinomas are associated with characteristic clinical syndromes resulting from the effects of the peptide they secrete. The majority of the islet cell tumours in fact secrete a number of different peptides and many of these are present in several molecular forms, some of which may not be biologically active. This may explain the lack of clinical sequelae in association with tumours such as the somatostatinomas. The clinical features, methods of diagnosis, localisation and treatment of these tumours will be discussed.

Topics: Adenoma, Islet Cell; Bombesin; Bronchial Neoplasms; C-Peptide; Carcinoma, Small Cell; Diagnosis, Differential; Endocrine System Diseases; Erythema; Gastrointestinal Hormones; Glucagon; Glucagonoma; Humans; Insulin; Insulin Secretion; Insulinoma; Male; Neoplasms; Neurotensin; Pancreatic Hormones; Pancreatic Neoplasms; Pancreatic Polypeptide; Somatostatinoma; Vasoactive Intestinal Peptide; Zollinger-Ellison Syndrome

A case of duodenal somatostatinoma is described in a patient with Von Recklinghausen neurofibromatosis. The patient presented with exocrine pancreatic insufficiency, probably due to distal obstruction of the pancreatic duct by the tumor. Preoperative evaluation with calcium-pentagastrin and tolbutamide stimulation tests were nondiagnostic. At laparotomy, local excision of the tumor was performed. Pathological findings were compatible with duodenal somatostatinoma, causing pancreatic fibrosis. Somatostatin extracted from the tumor coeluted with the somatostatin-14 standard on high performance liquid chromatography (HPLC).

Topics: Adult; Biopsy; Chromatography, High Pressure Liquid; Duodenal Neoplasms; Exocrine Pancreatic Insufficiency; Female; Fibrosis; Gastrins; Glucagon; Humans; Microscopy, Electron; Neurofibromatosis 1; Pancreas; Pancreatic Polypeptide; Radioimmunoassay; Somatostatin; Somatostatinoma; Vasoactive Intestinal Peptide

Topics: Endocrine System Diseases; Enterochromaffin Cells; Female; Gastrointestinal Neoplasms; Glucagonoma; Humans; Insulinoma; Male; Multiple Endocrine Neoplasia; Pancreatic Neoplasms; Somatostatinoma; Stomach Neoplasms; Vasoactive Intestinal Peptide; Zollinger-Ellison Syndrome

Topics: Adenoma, Islet Cell; Adult; Aged; Diabetes Mellitus; Diagnosis, Differential; Female; Glucagonoma; Humans; Insulinoma; Liver Neoplasms; Male; Middle Aged; Pancreatic Neoplasms; Skin Diseases; Somatostatinoma; Vasoactive Intestinal Peptide

Topics: Adrenal Glands; Adult; C-Peptide; Carcinoid Tumor; Epidermolysis Bullosa; Female; Gastrointestinal Diseases; Gastrointestinal Hormones; Gastrointestinal Neoplasms; Glucagonoma; Humans; Male; Middle Aged; Multiple Endocrine Neoplasia; Somatostatinoma; Thyroid Gland; Vasoactive Intestinal Peptide; Vipoma; Zollinger-Ellison Syndrome

Topics: Gastrointestinal Hormones; Glucagonoma; Humans; Insulinoma; Intestinal Mucosa; Somatostatinoma; Vasoactive Intestinal Peptide; Zollinger-Ellison Syndrome