Neuroendocrine tumors develop in the hormone-producing cells of the body's neuroendocrine system, causing the cells to send higher-than-normal amounts of hormones into the bloodstream, triggering a wide range of symptoms. Neuroendocrine tumors can be found in many places throughout the body, including the lungs, brain, and gastrointestinal tract.
In the pancreas, this type of cancer is called an islet cell tumor. Islet cells produce hormones, such as insulin, which regulates blood sugar. Islet cell tumors can be benign (non-functioning) or malignant (functioning). Gastrointestinal carcinoids develop from a specialized cell in the lining of the GI tract that produces hormones that regulate digestive enzymes and peristalsis, the contraction of muscles that moves food through the intestines. Gastrointestinal carcinoids are slow-growing tumors that most often develop in the appendix, small intestine and rectum.
No symptoms in early stage, but if the tumor has reached the liver or other parts of the body, the following symptoms may occur:
• Redness or a feeling of warmth in the face and neck
• Shortness of breath, fast heartbeat
• Swelling in the feet and ankles
• Pain or a feeling of abdominal fullness
Islet Cell Tumors:
The symptoms depend on the type of tumor and whether it is benign or malignant
Benign or non-functional tumors can cause abdominal pain, diarrhea, fatigue, fainting and unexplained weight gain
Malignant or functional tumors can cause a variety of symptoms, from stomach ulcers and low blood sugar to a skin rash or sore tongue depending on the type of excess hormone produced.