A pheochromocytoma is a malignant tumor in the core (medulla) of one or both of the adrenal glands, which causes an overproduction of the hormone, adrenaline. The body has two adrenal glands, one at the top of each kidney. Part of the endocrine system, these glands regulate key body functions, from maintaining blood pressure to coping with emotional stress. Adrenaline, the "fight or flight hormone" increases blood pressure. When overproduced, it carries a risk of heart attack or death, especially for patients with existing high blood pressure. Pheochromocytomas are mainly benign, and usually form on only one adrenal gland. Nevertheless, when they are malignant, they can spread to other parts of the body.
Causes and Risk Factors of Pheochromocytom
Pheochromocytomas originate in chromaffin cells, found in the center of the adrenal gland. Chromaffin cells also exist in nerve cells (paraganglioma). In general, the reason these chromaffin cells begin to grow is unknown, although heredity can be a factor. Though pheochromocytoma can develop at any age, it is most common in people between the ages of 30 and 60. In addition, pheochromocytomas are associated with multiple endocrine neoplasia, type II (MEN II), which is a pheochromocytoma and medullary thyroid cancer. MEN II has two subtypes: MEN IIA, which is a medullary thyroid cancer and hyperparathyroidism; and MEN IIB, consisting of pheochromocytoma, medullary thyroid cancer, and tumors of the nerves in the lips, mouth, eyes, and/or digestive tract. Pheochromocytomas are also linked to von Hippel-Lindau disease, a rare multi-system disorder, and neurofibromatosis 1 (NF1), a syndrome that causes multiple tumors, pigmented skin spots, tumors in the optic nerve, and bone lesions.
Symptoms of Pheochromocytoma
Pheochromocytomas often cause an overproduction of adrenaline (epinephrine), which results in high blood pressure. Symptoms of pheochromocytoma also include:
- Heart palpitations
- Lower chest or upper abdominal pain
- Severe headaches
- Weight loss
Pheochromocytomas can be triggered by drugs or stimulants that increase blood pressure. These can include monoamine oxidase inhibitors (MAOIs) for depression, such as phenelzine (Nardil), tranylcypromine (Parnate) or isocarboxazid (Marplan). The amino acid tyramine, another blood-pressure regulator, also can be a trigger. Tyramine is found in beer, wine, processed meats and cheese.
The combination of headache, sweating and heart palpitations is often an indication of a pheochromocytoma, especially in patients between the ages of 30 and 60. A family history of the condition may also indicate the presence of a pheochromocytoma, in which case genetic testing may be recommended.
Testing for a pheochromocytoma includes the measurement of catecholoamine and metanephrine hormones, which is monitored by collecting urine over a 24-hour period. If the amount of catecholoamine hormones is twice normal, an image (MRI or CT) of the adrenal gland is often the next step. If imaging reveals the presence of a mass, surgery may be recommended. If no mass is present, a specific scan for a pheochromocytoma, called a 123-1MIBG is usually done.
A pheochromocytoma is usually treated by surgically removing the tumor. The resection of the tumor can be performed with a traditional, open approach or laparascopically. Before surgery, salt is "loaded" into the patient, either through a high-salt diet, direct salt replacement or administration of an IV saline solution. This salt intake helps balance the change in the body after the tumor is removed and adrenaline levels return to a more normal level. Just before surgery, various drugs are used to allow manipulation of the adrenal gland while minimizing possible damage to the body.