ON THIS PAGE: You will find some basic information about these diseases and the parts of the body they may affect. This is the first page of Cancer.Net’s Guide to Pheochromocytoma and Paraganglioma. Use the menu to see other pages. Think of that menu as a roadmap for this complete guide.
About endocrine and neuroendocrine tumors
A tumor begins when the DNA of healthy cells is damaged, causing the cells to change and grow out of control, forming a mass. A tumor can be cancerous or benign. A cancerous tumor is malignant, meaning it can grow and spread to other parts of the body if it is not found early and treated. A benign tumor means the tumor can grow but will not spread. A benign tumor usually can be removed without it causing much harm.
It is difficult to tell if pheochromocytoma and paraganglioma are benign or malignant, even after surgically removing the tumor and examining it under a microscope. The only sure way to know if a pheochromocytoma or paraganglioma is malignant is if it has spread, called metastasis, or if it comes back, called a recurrence.
Pheochromocytomas and paragangliomas are considered a subset of a group of tumors called neuroendocrine tumors (NETs). A NET begins in the specialized cells of the body’s neuroendocrine system. These cells have traits of both hormone-producing endocrine cells and nerve cells. They are found throughout the body’s organs and help control many of the body’s functions. Hormones are chemical substances that are carried through the bloodstream to have a specific effect on the activity of other organs or cells in the body. All NETs have the potential to become metastatic. Most NETs take years to develop and grow slowly. However, some NETs can be fast-growing. See the Stages section of this guide to learn more.
A pheochromocytoma is a rare NET of the adrenal glands. The body has 2 of these small, yellowish glands. One is on top of each kidney. Adrenal glands have 2 main parts that function separately: the outer adrenal cortex and the inner adrenal medulla. Each part produces a different set of hormones.
A pheochromocytoma begins in the chromaffin cells of the adrenal medulla. The cells release hormones called catecholamines during times of stress. Adrenaline and noradrenaline, which increase blood pressure and heart rate, are 2 of those catecholamines. A pheochromocytoma can cause uncontrolled surges of extra adrenaline and noradrenaline into the blood. Even though an estimated 90% of pheochromocytomas remain localized to the area they began, these hormone surges can still lead to life-threatening health problems, such as a stroke, heart attack, hemorrhage, or sudden death.
Most people develop a pheochromocytoma in 1 adrenal gland. Some people develop a tumor in both glands. There can also be multiple tumors in a gland. Pheochromocytomas usually grow slowly.
A pheochromocytoma is called a primary adrenal gland tumor because it starts inside an adrenal gland. Read about other types of primary adrenal gland tumors.
A paraganglioma is a rare NET that develops from the same type of cells that pheochromocytomas do. However, paragangliomas form outside the adrenal glands. These tumors are also called extra-adrenal paragangliomas. The majority of paragangliomas form in the abdomen. They can also form in other parts of the body, including near the carotid artery, along nerve pathways in the head and neck, and in the chest, heart, abdomen, pelvis, and bladder. Paragangliomas are less common than pheochromocytomas. An estimated 60% remain localized and 40% may spread, though that cannot be determined at the time of diagnosis or from the pathology evaluation (see Diagnosis). Paragangliomas are typically slow growing.
There are 2 types of paragangliomas:
Sympathetic paragangliomas. Like pheochromocytomas, sympathetic paragangliomas almost always produce catecholamines. These tumors develop in the sympathetic nervous system, which controls the body’s response to stress and activity.
Parasympathetic paragangliomas. These tumors are most often found in the head and neck. They usually do not release catecholamines, so they rarely cause hormone-related symptoms or signs of a problem. They develop in the parasympathetic nervous system, which controls the body during rest.
Looking for More of an Introduction?
If you would like more of an introduction, explore this related item. Please note that these links will take you to other sections on Cancer.Net:
Cancer.Net Patient Education Video: View a short video led by an ASCO expert in NETs that provides basic information and areas of research.
The next section in this guide is Statistics. It helps explain the number of people who are diagnosed with a pheochromocytoma or paraganglioma and general survival rates. Use the menu to choose a different section to read in this guide.