Pheochromocytoma is rare. It occurs as often in men as women, causing less than 1 out of 100 of all high blood pressure cases. It can develop at any age, but is more common in people 40 to 60 years old. Researchers don’t know what causes most cases. Very few cases are linked to family history. Hereditary cases are seen more often in young patients. If pheochromocytoma is diagnosed before age 50, genetic screening is helpful.