What is a Neuroendocrine Tumor?

A neuroendocrine tumor is a cluster of abnormally growing cells located in or near the endocrine glands. Such tumors predominantly occur in the lungs or stomach. They can, however, grow anywhere in the body. There are roughly 10 different types of neuroendocrine tumors, ranging from carcinoids to vasoactive intestinal polypeptide tumors. They all are linked to a hyper-production of one of the hormones in the body and lead to unusually high and detrimental hormone levels, which can sometimes be corrected through prescription drugs or special diets.

Carcinoids are the most regularly occurring type of neuroendocrine tumor, followed by the oat cell. Oat cells are tiny cancerous cells specifically located in the lungs. Occurring mostly in the intestines, stomach, ovaries or the testes, carcinoids are tumors linked to cells that produce amines or peptides.

There are several other varieties of endocrine tumors as well. The type of neuroendocrine tumor that occurs in the stomach and spurs an excess release of the hormone gastrin is called gastrinoma. Gastrinomas are typically located at the start of the small intestines or in the pancreas. An insulinoma is a neuroendocrine tumor that creates excessive levels of insulin. Another type of tumor called a paraganglioma is a neuroendocrine growth that most commonly forms on the neck, face, and earlobes. In rare cases, they can appear on the abdomen or on blood vessels in any of the aforementioned locations.

Other types of neuroendocrine tumors include the pheochromocytoma, the glucagonoma, medullary carcinoma, and the pancreatic endocrine tumors. A kind of adrenal tumor, pheochromocytomas attack areas at the top of the kidneys, causing the overproduction of chemicals such as epinephrine. The rarely-occurring glucagonomas are tumors that attack islet cells inside the pancreas. Medullary carcinomas are cancerous growths that attach to the thyroid gland and secrete hormones known as calcitonin that deplete calcium levels in blood plasma. While they do not occur very often, pancreatic endocrine tumors can occur in middle-aged women as a result of stunted stem cells in the endocrine system.

The vasoactive intestinal polypeptide tumor, often called simply “peptide tumor,” is a another type of neuroendocrine tumor. These tumors result from an abnormal and excessive production of islet cells, usually in the pancreas. These peptide tumors can, however, also form in the kidney region, near the adrenal glands.

When multiple neuroendocrine tumors appear together, it is sometimes symptomatic of a condition known as multiple endocrine neoplasia syndrome. This genetic syndrome can result in several different kinds of irregular growths in the endocrine system. Not all of the growths are malignant, however.

Doctors can discover a neuroendocrine tumor through an endoscopy, imaging scan, or biopsy. Besides pharmaceuticals, treatments also can include freezing the tumors or excising them. Sometimes, surgeons can use radiation to heat and destroy the tumors as well.