vasoactive-intestinal-peptide and Gastrinoma

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

Multiple Endocrine Neoplasia type 1 (MEN1) is a rare autosomal dominant hereditary cancer syndrome presented mostly by tumours of the parathyroids, endocrine pancreas and anterior pituitary, and characterised by a very high penetrance and an equal sex distribution. It occurs in approximately one in 30,000 individuals. Two different forms, sporadic and familial, have been described. The sporadic form presents with two of the three principal MEN1-related endocrine tumours (parathyroid adenomas, entero-pancreatic tumours and pituitary tumours) within a single patient, while the familial form consists of a MEN1 case with at least one first degree relative showing one of the endocrine characterising tumours. Other endocrine and non-endocrine lesions, such as adrenal cortical tumours, carcinoids of the bronchi, gastrointestinal tract and thymus, lipomas, angiofibromas, collagenomas have been described. The responsible gene, MEN1, maps on chromosome 11q13 and encodes a 610 aminoacid nuclear protein, menin, with no sequence homology to other known human proteins. MEN1 syndrome is caused by inactivating mutations of the MEN1 tumour suppressor gene. This gene is probably involved in the regulation of several cell functions such as DNA replication and repair and transcriptional machinery. The combination of clinical and genetic investigations, together with the improving of molecular genetics knowledge of the syndrome, helps in the clinical management of patients. Treatment consists of surgery and/or drug therapy, often in association with radiotherapy or chemotherapy. Currently, DNA testing allows the early identification of germline mutations in asymptomatic gene carriers, to whom routine surveillance (regular biochemical and/or radiological screenings to detect the development of MEN1-associated tumours and lesions) is recommended.

Topics: Adolescent; Adrenal Cortex Neoplasms; Adult; Aged; Aged, 80 and over; Angiofibroma; Carcinoid Tumor; Child; Facial Neoplasms; Female; Gastrinoma; Genetic Testing; Humans; Insulinoma; Lipoma; Male; Meningioma; Middle Aged; Multiple Endocrine Neoplasia Type 1; Pancreatic Neoplasms; Parathyroid Neoplasms; Pituitary Neoplasms; Prolactinoma; Proto-Oncogene Proteins; Thyroid Neoplasms; Vasoactive Intestinal Peptide; Young Adult

We have investigated the prevalence of MEN 1 in patients with recognized pituitary adenomas. Since hyperparathyroidism is present in nearly 95-100% of patients with MEN 1 and frequently is the first condition to be identified, the study was limited to the identification of patients with hyperparathyroidism while the screening for gastroenteropancreatic (GEP) lesions was carried out in patients with both pituitary and parathyroid lesions.. Serum total and ionized calcium, phosphate and intact PTH 1-84 (EASIA) were measured in 166 patients (68 with non-functioning pituitary adenoma, 42 with prolactinoma, 35 with GH-secreting adenoma, 17-with ACTH-screening adenoma, 1 with TSH-secreting adenoma, 1 with FSH-secreting adenoma and 2 with an only alpha-subunit secreting adenoma) referred to our clinic from 1990 to 1996. Plasma gastrin, somatostatin, pancreatic polypeptide and vasoactive intestinal peptide were measured by RIA in patients with hyperparathyroidism.. Eight of 166 patients (4.8%) were found to have primary hyperparathyroidism and among these 2 also had a gastrinoma while there was no evidence of other GEP tumours. Considering the tumour type, 6 had prolactinoma (14.3%), 1 GH-secreting adenoma (2.8%) and 1 non-functioning adenoma (1.5%). In most patients the diagnosis of pituitary tumour was made several years before that of hyperparathyroidism (from 1 to 15 years) although 6 patients had previously suffered from urolithiasis and one had undergone gastric resections for recurrent peptic ulcers. One patient was identified as a MEN 1 gene carrier and 2 had relatives with signs and symptoms referable to parathyroid or GEP lesions.. The study shows a prevalence of 4.8% of primary hyperparathyroidism in unselected patients with known pituitary tumours similar to that reported in a previous study. By contrast, the prevalence of MEN 1 in patients with prolactinoma was definitely high (14.3%). In most patients the diagnosis of pituitary tumours was made several years before that of hyperparathyroidism. Although the patients were believed to harbour a sporadic pituitary tumour, most of them had had signs and/or symptoms referable to one or both of the other organs involved in MEN 1, often concomitantly with those of pituitary tumours. These data indicate that the diagnosis of MEN 1 syndrome is missed in a substantial proportion of patients with prolactinomas and therefore the screening of these patients for the syndrome is strongly recommended.

Topics: Adenoma; Adolescent; Adult; Aged; Biomarkers; Calcium; Female; Gastrinoma; Gastrins; Humans; Hyperparathyroidism; Male; Middle Aged; Multiple Endocrine Neoplasia Type 1; Pancreatic Polypeptide; Parathyroid Hormone; Phosphates; Pituitary Neoplasms; Prevalence; Prolactinoma; Somatostatin; Vasoactive Intestinal Peptide