See below. Pheochromocytoma is a tumor of the adrenal gland. These tumors release chemicals called catecholamines which can cause high blood pressure, headaches, sweating and palpitations and rapid heart beat. The condition sometimes runs in families. The tumor can be diagnosed with urine measurements of the catecholamines. Most tumors are benign and are cured by surgical removal.
Very rare. Pheos are very rare - about 1 in a million. They cause paroxysms of high blood pressure and rapid heart rate but sometimes cause sustained high blood pressure. Other symptoms are palpitations, nervousness and irritability, headache, sweating, weight loss. If you think you have one, you probably don't! blood and urine tests can confirm or exclude them.