A pheochromocytoma (adrenaline-producing tumor) that grows outside of the adrenal glands is known as extra-adrenal paragangliomas, or extra-adrenal pheochromocytomas. They are closely related to pheochromocytomas. While pheochromocytomas originate in the core of the adrenal glands, extra-adrenal paraganglioma tumors originate in the ganglia specifically the paraganglia, of the sympathetic nervous system Adrenal glands are located just above each kidney and are part of the endocrine system. One function of the adrenal glands is to produce hormones called catecholamines, such as epinephrine and norepinephrine.
The sympathetic nervous system’s main function is to control the organs of the body. Ganglia is a tissue mass of nerve cells. The paraganglia is a small group of chromaphil cells in the abdomen.
In 95 percent of cases, extra-adrenal paragangliomas are located in the abdomen regions, but they can also occur in the head, neck, and thoracic regions. Extra-adrenal paragangliomas represent approximately 15 percent of adult and 30 percent of pediatric pheochromocytomas. They tend to be malignant in more cases than pheochromocytomas.