Pheochromocytomas (Pheos) of the Adrenal Gland.

What are Pheochromocytomas and Paragangliomas?

Pheochromocytomas are tumors of the adrenal gland that produce excess adrenaline (also referred to catecholamines; epinephrine, metanephrine, and dopamine). Pheochromocytomas arise from the central portion of the adrenal gland, which is called the adrenal medulla. The adrenal medulla is responsible for the normal production of adrenaline, which our body requires to help maintain blood pressure and to help cope with stressful situations. A tumor that arises from the adrenal medulla and overproduces adrenaline is called a pheo, and it can be a deadly tumor because of the severe elevation in blood pressure it causes.

Paragangliomas are tumors that are nearly identical to pheochromocytomas except that these tumors grow outside of the adrenal gland (pheo's are always inside of the adrenal gland). Paraganglioma tumors typically occur inside the abdomen, located in the retroperitoneum (the back side of the abdomen), close to the big vessels, the aorta, and the inferior vena cava. Paragangliomas are discussed on a separate page of this website, but many of the symptoms and treatments are identical to pheochromocytomas (we don't discuss paragangliomas any further on this page).

Although most pheochromocytomas are benign (not cancerous), these tumors are highly toxic, and sometimes deadly due to the secretion of adrenaline hormones. The most common causes of complications and death of these tumors are related to heart, vessel, and brain effects by the adrenaline hormones such as sustained or episodic hypertension (high blood pressure), stroke, heart attack, heart arrhythmias, congestive heart failure, shock lung, hypotension and fainting. We diagnose and treat these tumors all the time. It is unfortunately not uncommon that pheochromocytomas are not diagnosed until the patient is admitted to the intensive care unit (ICU) with some of these devastating complications. This is sometimes referred to as adrenergic crisis. Often when looking back at their medical history and asking about the symptoms, patients may have had these for years to decades!

---

Why are Pheochromocytomas Called the 10% Tumor?

Pheochromocytomas are often referred to as the "ten percent tumor" because they do many things about ten percent of the time. The following is a list of these characteristics...

Ten Percent of All Pheochromocytomas Are:
• Malignant (90% are benign).
• Bilateral (found in both adrenal glands: 90% are arise in just one of the two adrenal glands).
• Extra-Adrenal (found within nervous tissue outside of the adrenal glands; these are called paragangliomas).
• In children (90% are in adults).
• Familial (10% will have a family member with the same type of tumor; recent studies; some of which Dr. Carling has conducted, suggests this number may be closer to 20%).
• Recur (10% will come back 5 to 10 years later; this number is a lot less with a highly skilled, experienced adrenal surgeon).
• Associated with MEN syndromes (patients with rare syndromes of endocrine tumors).
• Present with a stroke (10% of these tumors are found after the patient has a stroke).

Here's a look at the extra-adrenal sites (locations NOT in the adrenal--and therefore called "paragangliomas":

• Within the sympathetic nerve chain along the spinal cord
• Overlying the distal aorta (the main artery from the heart)
• Within the ureter (collecting system from the kidney
• Within the urinary bladder
• Remember, 90% are in the adrenal glands

---

Are Pheochromocytomas of the Adrenal Gland Rare?

Pheochromocytomas were, in the past, thought to be very rare. However, these tumors are not that rare for us. We see pheochromocytomas several times a week, and extra-adrenal paragangliomas (which is more rare) every month. The reason it was thought that pheochromocytomas and paragangliomas to be rare is that 1) many doctors do not know much about these toxic tumors, 2) many patients do not feel sick, or only occasionally have symptoms, 3) the symptoms are highly individual and variable. Pheochromocytomas has been called the great “mimicker” because the symptoms mimic those of many other diseases and thus the disease was never diagnosed, the most common symptoms is high blood pressure, which is often not further investigated by the doctor and just treated with blood pressure pills (anti-hypertensives).

Who Gets Pheochromocytomas?

Pheochromocytomas affect men and women equally, and most commonly are diagnosed in middle aged individuals. However, pheochromocytomas can occur in children and adolescents as well as in very old patients. Since almost 20 % of pheochromocytomas (and 40-50 % of paragangliomas) are hereditary (meaning they occur in families due to mutations in tumor-susceptibility genes), these patients and families should be screened for the pheochromocytomas and paragangliomas, and it often occur at an earlier age. In some cases of hereditary pheochromocytomas an individual with a certain gene mutation has a greater than 50% risk of developing a pheo during their lifetime.

Who should be screened for Pheochromocytomas and Paragangliomas?

Pheochromocytomas, as mentioned, pheochromocytomas has been called the great “mimicker” because the symptoms mimic those of many other diseases. Fortunately, screening for pheochromocytomas and paragangliomas is very easy. It just involves measurements of adrenaline hormones (technical name: fractionated catecholamines; dopamine, norepinephrine and epinephrine, and fractionated metanephrines; metanephrine and normetanephrine) in the blood and/or urine (24-hour collection). This can be performed by a simple blood test (plasma metanephrines).

If you have some of these symptoms or if you belong to any of the following goups, you need to be screened (tested) to ensure you do not have a pheochromocytoma.

• Hypertension at a young age (< 50 years of age).
• Hypertension with an adrenal incidentaloma.
• High adrenaline “spells”. This may be very variable but include.
• Palpitation (heart racaing and pounding).
• Pallor (face turning pale, then often followed by flushing.
• Tremor (shakiness).
• Headache.
• Sweating.
• Spells may be spontaneous or precipitated by change in body position, anxiety, medications (e.g., metoclopramide, anesthetic agents), and maneuvers that increase intraabdominal pressure (e.g. going to the bathroom).
• Hypertension in a family with any family member with an adrenal tumor (pheochromocytoma/paraganglioma).
• Resistant hypertension (i.e. poor response to medications).
• Hypertension requiring many medications.
• Hypertension and a family history of early-onset (< 50 years of age) hypertension or cerebrovascular accident (stroke) at a young age.
• Hypertension that is episodic (paroxysmal).
• A familial syndrome that predisposes to catecholamine-secreting tumors (e.g., multiple endocrine neoplasia type 2, neurofibromatosis type 1, von Hippel- Lindau disease, familial pheochromocytoma & paraganglioma syndromes).
• An incidentally discovered adrenal mass with imaging (X-ray) characteristics consistent with pheochromocytoma and paraganglioma.
• Pressor response during anesthesia, surgery, or angiography.
• Idiopathic dilated cardiomyopathy (enlargement of the heart).

Read more about symptoms of pheochromocytoma on our adrenal surgery blog

---