Large duodenal somatostatinoma in the third portion associated with severe glucose intolerance.

A 51-year-old man was admitted with hyperglycemia and a duodenal tumor. Although his glycemic control was poor, basal C-peptide levels were not suppressed. Further examination revealed a mass measuring 7.8 cm in diameter in the third portion of the duodenum. Duodenectomy revealed a slow-growing sessile tumor located near Treitz's ligament. The immunohistochemical profile of sections of the specimen revealed the presence of somatostatin. The patient's serum somatostatin was elevated to 300 pg/ml preoperatively, but was reduced to 10 pg/ml postoperatively. Glycemic control also normalized after the operation.

Somatostatinoma/inhibitory syndrome: a statistical evaluation of 173 reported cases as compared to other pancreatic endocrinomas.

Somatostatin is known to inhibit the secretory release of other peptide hormones. Somatostatinomas associated either with or without somatostatinoma (inhibitory) syndrome are rare neoplasms among gut-pancreatic endocrinomas. Collected from international literature, this study aimed to perform a statistical analysis on 173 patients with somatostatinoma/inhibitory syndrome. The evaluation further attempted to provide investigators in this particular field of research with extensive and precise information on the present situation of somatostatinoma. The 173 patients consisted of 81 with pancreatic somatostatinomas and 92 with extrapancreatic somatostatinomas. Most of the latter were found to have originated in the duodenum and may be termed as carcinoid somatostatinoma. Where data were considered to be adequate, a comparative study was carried out between two groups, pancreatic and duodenal, each consisting of 81 patients. A statistically significant difference between these two groups was found in the incidence of inhibitory syndrome (18.5% versus 2.5%) and von Recklinghausen's disease (1.2% versus 43.2%), large size of tumor (>20 mm) (85.5% versus 41.4%), multisecretory activities (33.3% versus 16.3%), and presence of psammoma bodies (2.5% versus 49.4%). There was no statistically significant difference in the rate of metastases and malignancy between the two groups. The average postoperative 5-year survival rate was 75.2% in 90 patients overall, 59.9% in 44 with metastases and 100.0% in 46 without metastases. Compared with the other pancreatic endocrinomas, including PPomas, glucagonomas, vipomas, gastrinomas, and insulinomas, somatostatinomas were characterized by the low rate of the relevant syndrome and multiple endocrine neoplasia syndrome type 1. There was a low rate of multiplicity, and a high incidence of psammoma bodies in the duodenal group particularly with von Recklinghausen's disease. A high rate of malignancy was recorded, resulting in a low postoperative survival rate of patients with metastases. In conclusion, somatostatinomas exhibited characteristic features quite different from those of the other pancreatic endocrinomas regarding multiple points.

Endocrine diffuse system. Histological and functional aspects interrelated with tumoral pathology.

It was first believed that all these endocrine cells are deriving from the neural crests; in time were discovered more than 40 different types of such cells with different origins and only 6 or 7 are deriving from the neural crests. Serotonin-secreting cells show yellow fluorescence, while those secreting cathecolamines show a green fluorescence, with formaldehyde. The most usual method for the stain of the cells of the endocrine diffuse system is the silver salts impregnation. In the electron microscopy the cells show dense granules, which are modified in appearance in the malignancies developed from such cells. Most of the hormones secreted in the intestine were found also to be hormones secreted in the central nervous system. The border between benign proliferation and malignant tumors arising from these endocrine cells is not well defined. DNES--diffuse neuroendocrine system.

[Somatostatinomas]. / Les somatostatinomes.

Somatostatinomas are endocrine tumors which prevailing secretion is somatostatin. They are localized in the pancreas and digestive tract or not often in tissues unusually secreting somatostatin, as bronchi. Forty three cases have been described until now. The endocrine syndrome, not very spécific and inconstant, is the result of the somatostatin hypersecretion. Diabetes mellitus, cholelithiasis, pancreatic exocrine insufficiency, gastric hypochlorhydria and anemia are the main symptoms of pancreatic somatostatinoma. On the other hand, they are not found in digestive tumors. Somatostatinomas often secrete other hormonal peptides which may change the clinical manifestations. Radioimmunoassay of plasma somatostatin (basal level and/or after stimulation by tolbutamid) is a more successful diagnostic test; but only immunocytochemistry of the tumor can proved the diagnosis. They a bad prognosis but are not a contra-indication to make a curative treatment; surgical resection and chemotherapy by streptozotocin and 5 FU are the two treatments.

Tumores funcionantes del páncreas

Con los avances técnicos como la microscopía electrónica, citoquímica e inmunopatología, ha sido posible identificar en los islotes de Langerhans diferentes células productoras de hormonas. Puede ocurrir hiperplasia (nesidioblastosis), formarse adenomas benignos o malignos a partir de estas células, cuya secreción hormonal no depende de estíulos fisiológicos. El tumor frecuente es el Insulinoma, que secreta insulina y el péptido C, da lugar a hipoglicemia, síntomas por respuesta adrenérgica y a neuroglucopenia; el diagnóstico se basa en la hipoglicemia algunas veces provocada por el ayuno, el ejercicio, o el aumento desproporcinado de la insulina circulante en relación con la glicemia, lo que se hace más aparente después del estímulo con tolbutamida o calcio. Se informan cinco casos vistos en nuestra Institución. Otro es el Gastrinoma que secreta gastrina, cursa con hipersecreción gástrica, úlcera péptica de localización atípica, complicada y rebelde al tratamiento, así como diarrea; el diagnóstico se hace por el quimismo gástrico basal y dosificación de la gastrina sérica, tanto en condiciones basales como despúes del estímulo con calcio o secretina, 60% de los gastrinomas son malignos. Se informan siete casos. El Glucagonoma, otro tumor pancreático produce glucagón y se manifiesta por diabetes de fácil control, eritema migratorio necrolítico, desnutrición y anemia hipocrómica; el aumento del glucagón sérico da el diagnóstico. El somatostatinoma se manigfiesta por diabetes, diarrea, esteatorrea y disfunción vesicular con formación de cálculos; el aumento de la somatostatina sérica confirma el diagnóstico. También se han descrito adenomas de células F productoras de polipéptidos pancreáticos, que cursan con diarrea, y Vipomas a partir de las células H, que producen el polipéptido intestinal vasoactivo y se manifiestan por diarrea acuosa, aclorihidria e hipokalemia...

[Pancreatic endocrine tumors with digestive effects. Physiopathological and clinical aspects]. / Tumeurs endocrines pancréatiques à effets digestifs. Aspects physiopathologiques et cliniques.

Endocrine tumours of the gastro-intestinal tract, especially pancreatic, play an important role in the regulation of digestive function and in the embryogenesis of the endocrine cells of the body. Histologically, about 50 p. 100 of these tumours are composed of several types of endocrine cell. However, in the majority of cases, the clinical and biological syndrome that they produce is related to the hypersecretion of only one of the peptide hormones secreted. One point of interest is the lack of correlation between tumour size, plasma concentration of the secreted peptide hormones, the effects of these endocrine oversecretions on the target organ(s) and the severity of the clinical presentation. This suggests phenomena of adaptation at each stage (tumour, peritumoral tissues and target organ). The diagnosis of gastro-intestinal endocrine tumors has been significantly improved by the development of reliable radioimmunological assays of the digestive hormones and modern techniques of medical imagery (ultrasonography, CAT scanning, selective portal angiography, aspiration biopsy under ultrasonic control). The prognosis of these tumours which are often malignant is better than that of gastro-intestinal adenocarcinoma. This justifies therapeutic intervention with the twin aim of controlling the effects of endocrine hypersecretion and tumour reduction. Surgical excision of the tumour should always be considered; if the tumour process is malignant chemotherapy will be required currently based on the association of 5-fluoro-uracil and streptozotocin.

Somatostatinoma syndrome. Clinical, morphological and metabolic features and therapeutic aspects.

A case of somatostatinoma syndrome in a 30-year-old woman is presented. Basal levels of growth hormone and of pancreatic and gastric hormones were reduced and the response of growth hormone, insulin and C-peptide to stimuli such as arginine, glucose, glibenclamide and calcium was virtually abolished. Similarly, gastric acid secretion, pancreatic exocrine function and intestinal absorption were significantly reduced. On the other hand, basal and stimulated levels of adrenocorticotropic hormone (ACTH), luteinizing hormone (LH), follicle-stimulating hormone (FSH) and thyroid-stimulating hormone (TSH) were within the normal range. Plasma somatostatin-like immunoreactivity was increased to 600-2,000 pg/ml (normal: 88-140 pg/ml). Immunocytochemical studies demonstrated the presence of somatostatin immunoreactive material in the primary tumour in the head of the pancreas and in the liver metastases. In spite of two courses of chemotherapy with streptozotocin and 5-fluorouracil the patient died due to liver failure 5 months after the first admission to hospital.

Somatostatin--physiological and pathophysiological aspects.

Somatostatin was originally isolated from the hypothalamus and has now been found in large quantities in the gastrointestinal tract and pancreas. Its localisation in nerve endings and endocrine-like cells suggests that somatostatin is a putative neurotransmitter and/or neuromodulator, local or paracrine acting substance and true endocrine factor or hormone. The present communication summarises the evidence for the release of somatostatin into the gastrointestinal lumen and the potential action of luminally released somatostatin. Furthermore, the evidence is presented for the release of splanchnic somatostatin into the circulation in response to a meal in rat, dog and man. The biological role of postprandially released and circulating somatostatin is to prevent an exaggerated response of certain exo- and/or endocrine functions of the gastrointestinal tract and pancreas as indicated by studies employing low-dose infusions of synthetic somatostatin or by neutralisation of somatostatin following the injection of specific antibodies. The release of gastric and pancreatic somatostatin is regulated by ingested and circulating nutrients and is modulated by neural mechanisms (cholinergic, adrenergic, dopaminergic) histamine, prostaglandins, opiates and gastrointestinal hormones. Several studies demonstrating a tight interaction between somatostatin and insulin indicate that insulin is another important factor in the regulation of basal and postprandial somatostatin release. The role of somatostatin in pathophysiological states such as peptic ulceration and diabetes mellitus is not entirely clear but the present evidence indicates that alterations of tissue somatostatin content or plasma somatostatin levels are secondary to changes of other factors (increased gastric acid secretion, insulin deficiency) rather than representing the primary cause for the underlying disease. Measurements of somatostatin in plasma are useful as a marker for the diagnosis of somatostatin-producing tumours.