Pheochromocytoma is a tumor of the adrenal gland that causes excess release of epinephrine and norepinephrine, hormones that regulate heart rate and blood pressure.

Pheochromocytoma may occur as a single tumor or as multiple growths. It usually develops in the medulla (center or core) of one or both adrenal glands. Sometimes this kind of tumor occurs outside the adrenal gland, usually somewhere else in the abdomen. Less than 10% of pheochromocytomas are malignant (cancerous), with the potential to spread to other parts of the body.

The tumors may occur at any age, but they are most common from early to mid-adulthood. A common clinical feature is a paroxysm (an attack of symptoms listed below) that may be frequent but sporadic (occurring at unpredictable intervals). The paroxysms may increase in frequency, duration and severity as the tumor grows.

• Severe headache
• Palpitations
• Rapid heart rate
• Sweating
• Flushing
• Chest pain
• Abdominal pain
• Nervousness
• Irritability
• Increased appetite
• Loss of weight

• Sleeping difficulty
• Hand tremor
• High blood pressure

Vital signs (temperature, pulse, rate of breathing, blood pressure) reveal high blood pressure, rapid heart rate, and fever.

Tests include:

• Adrenal biopsy can show pheochromocytoma.
• MIBG scintiscan can show a tumor.
• MRI of abdomen can show a adrenal mass.
• Abdominal CT scan can show a mass.
• Urine metanephrine will be high.
• Urine catecholamines will be high.
• Glucose test results will be abnormal.
• Catecholamines in the blood will be abnormal.