Neuroendocrine tumors are cancers that begin in specialized cells called neuroendocrine cells. Neuroendocrine cells have traits similar to those of nerve cells and hormone-producing cells.Neuroendocrine tumors are rare and can occur anywhere in the body. Most neuroendocrine tumors occur in the lungs, appendix, small intestine, rectum and pancreas.
There are many types of neuroendocrine tumors. Some grow slowly and some grow very quickly. Some neuroendocrine tumors produce excess hormones (functional neuroendocrine tumors). Others don't release hormones or don't release enough to cause symptoms (nonfunctional neuroendocrine tumors).Diagnosis and treatment of neuroendocrine tumors depend on the type of tumor, its location, whether it produces excess hormones, how aggressive it is and whether it has spread to other parts of the body.
Neuroendocrine tumors don't always cause signs and symptoms at first. The symptoms you might experience depend on the location of your tumor and whether it produces excess hormones.
In general, neuroendocrine tumor signs and symptoms might include:
Pain from a growing tumor
A growing lump you can feel under the skin
Feeling unusually tired
Losing weight without trying
