Overview
Neuroendocrine cancer is a rare type of cancer that originates in the neuroendocrine system, where the nervous and endocrine systems work together. While they are slow-growing, they can be difficult to diagnose, and eventually become life-threatening.
Because of the neuroendocrine system's diffuse nature, this type of cancer manifests itself in a variety of ways. Many of these tumors secrete excessive amounts of different hormones, causing a variety of symptoms. While some of the tumors are distinctive, arising in a particular site in the body, others are not so easily classified; they may or may not have "neuroendocrine features."
Since the types of tumors and symptoms vary so widely, treatment is based on the type of cancer that is identified. The following are some of the different kinds of tumors that fall under the larger category of neuroendocrine cancer.
Carcinoid Tumors
Most carcinoid tumors begin in one of four sites: the appendix, small intestine, rectum, or the bronchus. Less frequently, they arise in the stomach, pancreas, colon, liver, ovary, testis, or cervix. Carcinoid tumors can be benign or malignant. Symptoms may include a sudden flushing and reddening of upper body parts (especially the head and neck), a sudden increase in heart rate and blood pressure, and diarrhea. Depending on the tumor's location, symptoms can also consist of abdominal pain, anemia, pneumonia, cough, and spitting of blood. To discover the precise location and extent of the primary tumor, specialists use a wide range of imaging techniques and blood tests. These factors determine the course of treatment, which may include surgery and possibly chemotherapy or radiation therapy.
Pheochromocytoma
This term refers to cancer of the adrenal medulla, which is the area located on the inside of the adrenal glands. This type of cancer may arise as part of a condition called multiple endocrine neoplasia (MEN) syndrome, which can result in other cancers of the endocrine system and hormonal abnormalities. Pheochromocytoma often causes the adrenal glands to make too much of a group of hormones called catecholamines. Excessive amounts of these hormones may cause high blood pressure, rapid pulse, palpitations, anxiety attacks, fever, headaches, nausea and vomiting, and clammy skin. The majority of pheochromocytomas are not malignant. Blood and urine tests, as well as imaging tests like CT scanning, are used to diagnose or rule out this condition.
Merkel's Cell Tumors
Merkel's cell cancer, also called neuroendocrine cancer of the skin or trabecular cancer, is a rare type of cancer that forms on or just beneath the skin and in hair follicles. It may also develop in underlying soft tissue. This type of cancer occurs predominately in Caucasian people between the ages of 60 and 80.
Merkel's cell tumors usually appear as firm, painless, shiny skin lumps. The lumps are red, pink, brown, or blue; they range from approximately a quarter inch to two inches in size. They are most often, but not exclusively, found on the sun-exposed areas of the head and neck.
These tumors grow rapidly, and can quickly metastasize to other parts of the body. Merkel's cell cancer tends to spread to the regional lymph nodes, and may also spread to the liver, bone, lungs, and brain. Surgery is the preferred treatment for Merkel's cell tumors. To destroy any remaining cancer cells, radiation therapy is applied to the area. Merkel's cell cancer that has metastasized is usually treated with chemotherapy. Although this type of cancer may respond to chemotherapy, it is not usually cured. Early diagnosis and treatment of Merkel's cell tumors is crucial in decreasing the chance of the tumors spreading.
Neuroendocrine Carcinomas
Often extremely undifferentiated, these tumors can be diagnosed only when a pathologist examines a tissue sample using specialized stains that allow clarification of the cells' subtype. Urine may also be tested for elevated levels of specific products related to this type of cancer. Some neuroendocrine cancers, such as Merkel's cell tumors, possess defining structural characteristics, but many are never distinguished beyond the broader category of "neuroendocrine carcinoma."
Neuroendocrine carcinomas can originate in a range of locations including the gastrointestinal tract, lung, and brain. Some tumor cells produce hormones; others produce nothing and cause no symptoms. Treatments include surgery, radiation therapy, or chemotherapy. Each of these treatments may be used by itself or in combination with another treatment.