Neuroendocrine gut and pancreatic tumors are rather rare malignant diseases, but development of new diagnostic tools (somatostatin receptor scintigraphy) and therapeutic options (somatostatin analogs, radioactive-labeled octreotide, transarterial therapy, radiofrequency ablation) make them of great interest to the medical community. The term neuroendocrine tumor encompasses a variety of relatively different diseases:

• Carcinoid tumors, which are the most common, with an incidence of about 3 per 100,000 persons

• Islet cell carcinomas, also called pancreatic endocrine tumors, with an incidence of about 0.3 per 100,000 persons

Carcinoid tumors arise most often from the small bowel, sometimes from pancreas, lung and bronchi, and more rarely from other organs such salivary glands or uterus but can arise from nearly everywhere due to the widespread diffusion of neuroendocrine cells, which give rise to the disease. Most often, they induce high levels of serotonin or chromogranin A. Islet cell carcinomas or pancreatic endocrine tumors arise from the pancreas and can produce insulin, glucagons, or vasoactive intestinal peptide (VIP). Production of various systemic hormones associated with specific immunohistochemical markers such as neurospecific enolase (NSE), synaptophysin, cytokeratin, chromogranin and CD 56 allows the diagnosis of these neuroendocrine tumors. For clinical considerations, the histopathologic grade of the tumor is an even more important factor than the histopathologic type. The grade obtained from the number of mitoses per microscope high-power field is linked to the aggressiveness of the disease and thus will influence therapeutic choices. Tumors with two or fewer mitoses are classified as low grade.