Carcinoid tumor gastric

The prodrugs are unstable in the presence of acid and therefore must be administered as an enteric-coated preparation or as a buffered suspension. Pantoprazole is also available in an intravenous formulation. The most commonly reported side effects are diarrhea and headache. Hypergastrinemia has been noted as a reaction to the marked reduction in acid secretion. Gastric carcinoid tumors have developed in rats but not in mice or in human volunteers, even after long-term use. 

There has been concern about the potential for proton pump inhibitors to cause enterochromaffin-hke cell hyperplasia, gastric carcinoid tumors and gastric cancers, colorectal polyps and adenocarcinoma, atrophic gastritis, and intestinal metaplasia in patients with H. pylori infection, and bacterial overgrowth. 

A gastric carcinoid tumor, detected during long-term anti-ulcer therapy with a histamine receptor antagonist and proton pump inhibitors, has been reported (34). 

A gastric carcinoid tumor was found in a man of 62 taking ranitidine (22). The dosage had been unusually high and there was pre-existing chronic renal insufficiency as well as diabetes, but the tumor was similar in type to that seen in animals it was successfully removed by partial gastrectomy and did not recur. 

The proton pump inhibitors are usually well tolerated however, potential adverse effects include headache, dizziness, somnolence, diarrhea, constipation, and nausea. The frequency of adverse events appears to be similar to that seen with the H2-receptor antagonists. Concern and controversy regarding the safety of therapy with a proton pump inhibitor are based on the proton pump inhibitor s ability to cause hypergastrinemia and gastric carcinoid tumors in rats. After nearly a decade of experience with the proton pump inhibitors, gastric carcinoid tumors have not been directly linked to omeprazole use in humans. ... 

FIGURE 33-6. The gastrin hypothesis suggests that prolonged hypergastrinemia results in hyperplasia of the enterochromaffin-l ike (ECL) cells of the gastric fundus. The trophic influence of gastrin may be a risk factor for ECL cell carcinoid tumor formation. 

INCREASED PROLIFERATION OF MAST CELLS AND BASOPHILS GASTRIC CARCINOID TUMORS... 

Gastric cancer compromises about 10% of all cancers world-wide [33]. The majority of the malignancies of the stomach are adenocarcinomas. Lymphomas, carcinoid tumors and sarcomas make up the remaining gastric neoplasms. The most efficacious curative therapy to date has been surgical resection. In experienced hands, surgical resection for palliation has mortality as low as 8% and nearly 25% may survive two years after the operation [34]. However, patients with metastatic disease... 

Omeprazole (Prilosec) Inhibits H+/K+ ATPase (proton pump) of parietal cell. Thus, reduces acid secretion. Reflux esophagitis, hypersecretory states. Few side effects. Constipation. Causes gastric carcinoid tumors in rats after prolonged use. 

Gastric adenocarcinoma is one of the leading causes of cancer morbidity and mortality worldwide. Gastric cancer comprises approximately 95% of all gastric tumors, and is the focus of this chapter. Other less common gastric tumors not discussed here include mucosa-associated lymphoid tissue (MALT) lymphoma, gastrointestinal stromal cell tumors, and carcinoid tumors. 

CD57 (leu 7) Neuroendocrine tumors T-cell lymphoma and pre T-ALL, chordoma, MPNST, germ cell tumors, papillary thyroid carcinoma, thymic carcinoma, germ cell tumors, synovial sarcoma, carcinoid tumors, schwannoma, mesothelioma, astrocytoma and glioblastoma NK-cells, Schwann cells, gastric chief cells, adrenal medulla, pancreatic islets, renal tubular epithelium, epithelial cells of thymic cortex, retina, oligodendrocytes... 

However, because no progression to dysplastic or neoplastic lesions has thus far been documented in these latter conditions, their role in gastric endocrine tumorigenesis appears unlikely. Carcinoid tumor is thus characterized morphologically by the criteria of size and invasion. 

The tumor is histamine secreting and does not metastasize, which renders it closely comparable to the human type I gastric carcinoid tumor. If untreated, animals develop duodenal ulcers, which either bleed or perforate, resulting in demise of the tumor carrier on an acute basis. The tumor could be successfully... 

Distribution of the 13,715 carcinoid tumors contained by the ERG, TNCS, and the SEER file (1950-1999) by organ site. The dominant site for carcinoid development is the gastrointestinal system. Gastric carcinoids constitute 4.1% of all carcinoid tumors. 

The characteristic features of the different types of gastric carcinoid tumors. 

Majka J, Sher S (1989) Spontaneous gastric carcinoid tumor in an aged Sprague-Dawley rat. Vet Pathol 26 88-90... 

Carney JA, Go VLW, Fairbanks VF, Moore SB, Alport EC, Nora FE (1983) The syndrome of gastric argyrophil carcinoid tumors and nonantral gastric atrophy. Ann Intern Med 99 761-766... 

Borch K, Renvall H, Liedberg G (1985) Gastric endocrine cell hyperplasia and carcinoid tumors in pernicious anemia. Gastroenterology 88 638-648... 

The positive staining for AE1/AE3 and CAMS.2 that is seen in gastric carcinoids can help distinguish them from secondary involvement of the gastrointestinal tract by other neuroendocrine tumors such as pheochromocytoma and retroperitoneal paraganglioma. 

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