Everyone has neuroendocrine cells in their bodies. Neuroendocrine cells are mainly distributed diffusely in the gastrointestinal tract, in the lungs and the pancreas. The role of these cells is to produce various messengers (hormones). Cells in the body are renewed at intervals, which involves the splitting of these cells. At some point an error probably occurred during a neuroendocrine cell division, perhaps many years ago. The newly created neuroendocrine cell and the new cells subsequently created from it have lost some genetic information and divide more frequently than normal and no longer die off. This leads to growth and displaces the normal surrounding cells. Fortunately, neuroendocrine cells generally grow relatively slowly compared to other types of tumors.
Neuroendocrine tumor cells frequently produce hormones. The high hormone levels thus cause a set of symptoms known as malignant carcinoid syndrome. You may experience them in the form of heat flashes, red flushing of the face, diarrhea, alcohol intolerance, asthma or skin problems.