Tumores neuroendocrinos del páncreas / Pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors are infrequent and slow-growing neoplasms. They are classified basedon their clinical presentation as functioning and nonfunctioning tumors. The most common functionaltumors are the insulinoma and gastrinoma. They can be sporadic or be part of hereditary forms as MEN-1.The diagnosis is based on the detection of the specific clinical syndrome in association of high levels of the substance secreted by the tumor and conventional imaging studies or others such as stimulation tests, somatostatin receptor scintigraphy and endoscopic ultrasound. In general, these tumors have a better prognosis than the pancreatic adenocarcinoma and they can show metastasis to the liver and infrequently, in bones. The treatment can be managed medically diminishing the inappropriate secretion of the substances by the tumor using, for example, the somatostatin analogs. Surgery should be always considered, especially in case of insulinomas, small non-functioning tumors, and small gastrinomas that can be managed with surgery enucleation. More advanced resective surgery, such as Whipple resection, are not routinely recommended and they should be limited to selected patients. In advanced tumors, there are other treatment alternatives, for example, hepatic resection, radiofrequency, chemotherapy and new agents such as sunitinib and everolimus.

Los tumores neuroendocrinos pancreáticos son infrecuentes y de crecimiento lento. Se clasifican en tumores funcionantes o no funcionantes (TNEP-NF), de acuerdo a la presentación clínica. Los tumores funcionantes más frecuentes son los insulinomas y los gastrinomas. Pueden ocurrir en forma esporádica o asociados a síndromes hereditarios como la NEM- 1, entre otros. El diagnóstico se basa en la detección del síndrome clínico específico asociado a la demostración de niveles elevados de la sustancia secretada y exámenes imagenológicos convencionales u otros más específicos como de estimulación, cintigrafía de receptores de somatostatina y endosonografía. En general, tienen mejor pronóstico que los adenocarcinomas pancreáticos y pueden dar metástasis hepáticas y con menor frecuencia, óseas. El tratamiento puede ser médico disminuyendo la secreción inapropiada de las sustancias producidas por el tumor como los análogos de somatostatina. La cirugía siempre debe ser considerada, especialmente en caso de insulinomas, pequeños TNEP-NF, y gastrinomas pequeños, que pueden ser tratados con enucleación quirúrgica. Las cirugías resectivas más avanzadas, como la operación de Whipple no están recomendadas en forma rutinaria y sólo deben ser utilizadas en pacientes seleccionados. En casos de tumores avanzados, existen alternativas de tratamiento, como la resección hepática, radiofrecuencia, quimioterapia, y terapia con nuevos agentes en estudio como el sunitinib y everolimus.

glucagon et les glucagonomes

Ghucagon is a pancreatic peptide, secreted by the A cells of the pancreatic islets of Langerhans under the influence of a certain number of regulating factors. This 29 amino-acids peptide has essentially a hyperglycemic action because it mobilizes all the organism's energetic reserves, and will therefore oppose insulin hypoglycemias. Its other actions are less known and are only expressed at supraphysiological levels such as its muscle relaxant effect on the digestive smooth muscle fibers, or its cardiac stimulant effect. Some authors have attributed recently to glucagons a role in the regulation of thirst and satiety, and that may lead to some interesting therapeutic actions such as in obesity. Its regulating action on liver cells has not been proven yet at least in severe hepatic lesions. Glucagonomas are rare neuroendocrine tumors, usually malignant, that develop in the endocrine pancreas and have a clinical picture characterized by the presence of the 4 D syndrome [migratory necrolytic dermatitis, diabetes mellitus, deep-vein thrombosis, and depression]. The tumor causing the hyperglucagonemia has a slow growth that explains its often important volume and the existence of metastasis in 60% of the cases at the time of diagnosis. Apart from the metastatic invasion, and as is the case in other neuroendocrine tumors, there are no definite criteria of histological malignancy. The definitive treatment of glucagonoma is surgical removal of the tumor, flanked or not by a treatment with somatostatin analogues that are active because of the existence of somatostatin receptors in neuroendocrine tumors. Radioactive somatostatin is utilized for the detection of metastatic sites but also as a therapeutic tool. Concerning whole-body scanning, the use of radiolabeled somatostatin has proven to be one of the high-performance techniques, but also a very sensitive one. As far as treatment is concerned, somatostatin radioactive analogues are increasingly replacing conventional radiotherapy as well as conventional chemotherapy