Rare Disease Database

Synonyms

• Neuroendocrine neoplasia
• Neuroendocrine neoplasm

Overview

A neuroendocrine tumor (NET) is a rare type of tumor that arises from specialized body cells called neuroendocrine cells. These cells have traits of both nerve cells and hormone-producing cells, and release hormones into the blood in response to signals from the nervous system.[14584][14583] Because a neuroendocrine tumor arises from cells that produce hormones, the tumor can also produce hormones.[14583]

Neuroendocrine tumors can develop anywhere in the body, but most occur in the digestive tract, pancreas, rectum, lungs, or appendix.[14584][14583][14585] They can be non-cancerous (benign) or cancerous (malignant).[14584] They usually grow slowly over many years, but there are fast-growing forms.[14583][14336]

There are many types of neuroendocrine tumors, but most are classified as one of two main types:[14583][14585]

• Carcinoid tumors – NETs that most commonly arise in the digestive tract, lungs, appendix or thymus. They can also grow in the lymph nodes, brain, bone, gonads (ovaries and testes) or skin.[14583][5150]
• Pancreatic neuroendocrine tumors (also called islet cell tumors) – NETs that typically arise in the pancreas, although they can occur outside the pancreas.[14646]

A pheochromocytoma is another, rarer type of NET that usually develops in the adrenal gland, but can also arise in other parts of the body.[14583]

Signs and symptoms depend on the tumor’s type, size and location; whether it produces hormones; and whether it has spread to other parts of the body (metastasized).[14583] NETs are typically described as functional or nonfunctional. Functional NETs produce a specific set of symptoms due to the production of excess hormones, while non-functional NETs generally do not cause specific symptoms. In many cases, a person has no symptoms until the tumor spreads to the liver and/or impairs the function of an organ or system. This can make NETs very hard to diagnose.[15392]

The majority of NETs are not inherited and occur sporadically in people with no family history of NETs.[14585] However, some NETs are associated with a hereditary cancer or tumor syndrome such as multiple endocrine neoplasia type 1 (most commonly), Von Hippel-Lindau disease, tuberous sclerosis, or neurofibromatosis type 1 (NF1). Inheritance of each of these is autosomal dominant.[14585]

Treatment of NETs depends on many factors such as the tumor’s type, location, aggressiveness, and hormone-producing capabilities; as well as whether it has metastasized.[14584] Management options may include surveillance, surgery to remove the tumor and/or surrounding tissue, and various non-surgical therapies to shrink the tumor, stop it from growing, or manage symptoms.[15395][15393][15394]

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