Pheochromocytoma

Alternative names:

chromaffin tumors

Definition:

A tumor of the adrenal gland that causes excess release of the two hormones epinephrine and norepinephrine, which regulate heart rate and blood pressure.

Causes, incidence, and risk factors:

The tumor may be single or multiple and usually develops in the medulla (center or core) of one or both adrenal glands. Sometimes the tumors occurs outside the adrenal gland, usually within the abdomen. Less than 10% of the tumors are malignant (cancerous). The tumors may occur at any age, but they are most common in young to mid-adult life. A common clinical feature is a paroxysm (attack of symptoms) that may be frequent but sporadic, and may increase in frequency, duration, and severity.