Gastrointestinal tract neuroendocrine tumors

C. Carcinoid tumors arise from neuroendocrine cells of the gut and secrete serotonin and gastrointestinal hormones, which activate the gastrointestinal tract and result in diarrhea. Most of these tumors have receptors for somatostatin, which inhibit secretion when activated, resulting in reduced activity of the gut. Octreotide is a stable analogue of... 

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. 

Mertz EE, Vyberg M, Paulsen SM. Immunohistochemical detection of neuroendocrine markers in tumors of the lungs and gastrointestinal tract. Appl Immunohistochem. 1998 6 175-180. 

Viale G, Doglioni C, Gambacorta M, et al. Progesterone receptor immunoreactivity in pancreatic endocrine tumors. An im-munocytochemical study of 156 neuroendocrine tumors of the pancreas, gastrointestinal and respiratory tracts, and skin. Cancer. 1992 70 2268-2277. 

Promising results have been published for liver metastases of other different original tumors. Neuroendocrine tumors, particularly those of gastrointestinal tract origin, have a predisposition for metastasizing to the liver, causing parenchymal substitution and paraneoplastic syndrome (Fiorentini et al. 2004). TACE is thought to be an effective symptomatic and antiproliferative treatment in patients with liver metastases of neuroendocrine tumors. 

In 1930, F. Feyrter (top left) of Gdansk proposed the existence of a diffuse system of neuroendocrine cells in the gastrointestinal tract (center). Thereafter, P. Masson (1880-1959) (bottom right) described in detail the characteristics of the cells that formed the basis of the diffuse neuroendocrine system (back-ground). In addition, Masson proposed that the enterochromaffin cells in the crypts of Lieberkuhn (which had been identified by N. Kulchitsky in 1897) were the progenitors of neuroendocrine tumors of the gut (carcinoids). 

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