Pheochromocytoma is a rare tumor that forms in the chromaffin cells of the adrenal glands. Pheochromocytomas are also known as adrenal chromaffin tumors (1). Chromaffin cells are found in the adrenal medulla (Figure 1). The adrenal glands located just above the kidneys. These cells receive neural messages from the brain via neurotransmitters and, through these messages, release hormones into the bloodstream (Figure 2). The main catecholamines produced in the adrenal glands are dopamine, norepinephrine, and epinephrine (also called adrenaline) (1). Pheochromocytomas cause the adrenal glands to produce too much of these hormones, called catecholamines. Adrenal glands with pheochromocytomas produce excess catecholamines, which can cause high blood pressure or hypertension (1). Untreated high blood pressure can lead to a variety of serious health problems, including heart disease and stroke. Typical symptoms of pheochromocytomas include headache, excessive sweating, racing heart, chest pain, and feeling anxious (1). Pheochromocytomas can be hereditary and several genes have been identified which, when mutated, lead to pheochromocytoma (Figure 3). The majority of hereditary pheochromocytomas are due to mutations in the VHL, RET, NF1 and MAX genes. Pheochromocytoma has been associated with Von Hippel-Lindau syndrome (VHL), multiple endocrine neoplasia type 2 (MEN 2), and neurofibromatosis type 1 (NF1). Von Hippel-Lindau disease (VHL) is a disease caused by mutation of the VHL gene, in which cysts and tumors develop in the brain, kidneys and adrenal glands. Neurofibromatosis 1 (NF1) is a disease in which tumors develop on the skin and optic nerve and is caused by ...... middle of paper ...... known as alpha-blockers . Medicines available under the name tyrosine kinase inhibitors can also be used to stop the tumor from forming hormones. In some cases, radiation therapy (using high-dose X-rays or other high-energy rays to kill cancer cells) or chemotherapy (using drugs to kill cancer cells) may be used to treat pheochromocytoma (4 ). Typically, pheochromocytomas are found. in the adrenal gland are benign and can be surgically removed (4). Patients with recurrent pheochromocytoma tumors, tumors that have metastasized, or that cannot be surgically removed have a fair to poor outlook. Malignant and benign pheochromocytomas can recur after surgical removal of the tumor. Therefore, long-term follow-up care is very important after surgery to maintain the outlook from fair to good with additional medical or surgical treatments as appropriate.. (4).