Pheochromocytoma

What is a pheochromocytoma?

The pheochromocytoma is a tumor that occurs in the medulla of the adrenal glands and that produces an increase in the secretion of catecholamines.

The adrenals are glands found in the upper pole of the kidneys. They consist of two different parts, the cortex and the medulla. Mineralcorticoids, glucocorticoids, and androgens are produced in the cortex, which in turn has three different layers. In the adrenal medulla, the innermost area of ​​the gland, catecholamines are produced, mainly epinephrine and norepinephrine.

Like all tissue in the body, in the also tumors may appear, be they benign or malignant. Given the glandular nature of the tissue, these tumors can produce hormonal secretion.

How is it produced?

The appearance of pheochromocytoma depends on several factors: genetic and environmental. It can also be associated with other syndromes or diseases such as neurofibromatosis, tuberous sclerosis, Sturge-Weber syndrome.

Pheochromocytoma is a tumor that in more than 90% of cases are benign. It is more common in adults than in children, especially between the fourth and fifth decades of life. In adults, approximately 80% of tumors are unilateral (affecting a single adrenal gland), 10% are bilateral, and 10% occur in other tissues similar to the adrenal medulla but not found in the gland. These tissues are found next to the vertebrae, at the bifurcation of the aorta, the thorax, the neck, and the urinary bladder.

In children, a quarter of pheochromocytomas are bilateral (affecting both adrenal glands) and another 25% occur in the extraglandular tissues, since these tissues are more abundant during childhood and disappear with growth. Nevertheless, half of pheochromocytomas in children remain unilateral.

Pheochromocytoma usually appears as an isolated entity, but on occasions it can be associated with other tumors and organic alterations, in 10% of cases in adults and in 25% in children. These associations are called multiple endocrine neoplasms (MEN). There are different types and pheochromocytoma is included within the so-called MEN type 2A, which associates this thyroid and hyperparathyroidism, and MEN type 2B, also associated with medullary thyroid carcinoma, as well as neuromas and marfanoidism. These types of MEN are associated with abnormalities of chromosome 10. It is also occasionally associated with von Hippel-Lindau disease and less frequently with neurofibromatosis type 1 or von Recklinghausen disease.

These tumors produce both adrenaline and noradrenalineHowever, it should be noted that those that are located in extraglandular tissues usually secrete only norepinephrine, while those that occur in the context of MEN only secrete epinephrine. The small percentage of malignant pheochromocytomas that exist can also produce dopamine.

Symptoms

The clinical manifestations produced by pheochromocytoma are derived from the overproduction of catecholamines.

The main symptom is the. All patients suffer hypertensive crises, but while in 60% of cases blood pressure remains high in the periods between crises, the remaining 40% of patients only present high figures when they suffer from these crises. Only a small percentage of patients have pheochromocytomas without blood pressure involvement.

During the attacks the symptoms that appear are headache, profuse sweating, anguish, palpitations, feeling of death, skin paleness, chest pain or abdominal pain accompanied by nausea and vomiting. The blood pressure rises to alarming levels. Hypertensive crises can be triggered by various factors, such as:

• Movements of the abdominal organs.
• Stress.
• .
• Sudden changes in position.
• Serial sneezing.
• Valsalva maneuver.
• Excessive intake of cheese or alcohol.
• Anesthetics and various drugs.

In extraglandular pheochromocytomas located in the urinary bladder, crises can triggered by urination and in half of the cases hematuria occurs.

Other disorders caused by pheochromocytoma

• Glucose intolerance (since catecholamines inhibit insulin).
• .
• Supraventricular arrhythmias or ventricular extrasystoles.
• Angina pectoris or acute myocardial infarction.
• Gallstones.
• Rhabdomyolysis
• Polyuria
• Hypercalcemia
• Increased blood concentration.

Diagnosis

Pheochromocytoma should be suspected in patients with severe high blood pressure attacks associated with any of the alterations mentioned above.

The diagnosis is based on the detection and determination of free catecholamines in urine 24 hours of the patient, as well as its metabolites. These substances will be elevated in patients with pheochromocytoma. When in doubt, you can determine in blood plasma after having administered an inhibitor of the sympathetic system, in which case they will appear abnormally high.

As imaging techniques to be able to observe the tumor, a computerized axial tomography (CT), a nuclear magnetic resonance (NMR) or a scintigraphy with a specific marker, metaiodobenzylguanidine. If the tumor cannot be seen through these imaging tests, an abdominal arteriography can be performed, since these tumors are highly irrigated, that is, they have a large number of arteries that supply them with blood.

Treatment

The curative treatment of pheochromocytoma undergoes surgical intervention. However, given the secretory characteristics of the tumor and the alterations in blood pressure control that it produces, with the consequent risks during surgical removal, a pharmacological preparation must be carried out prior to the intervention.

During the 10-14 days prior to the intervention, the patient will be administered substances to control blood pressure, the so-called alpha-blockers. Once the blood pressure is controlled, other drugs called beta-blockers can be given. In addition, calcium channel blockers can also be co-administered for blood pressure control.

The intervention consists of removal of the entire adrenal gland. During the procedure, the role of anesthetists is essential to control blood pressure and heart rate.

In case the tumor is malignant and cannot be intervened, the treatment will focus on the control of blood pressure.

Survival at 5 years after the intervention exceeds 95% in benign pheochromocytomas, but it does not reach the 50% in the case of malignant tumors that may have been operated. Surgical intervention eliminates arterial hypertension completely in 75% of patients, and in the rest it is easily controlled with antihypertensive drugs.

Precautionary measures

There are no preventive measures against this tumor. Anyone with symptoms compatible with this tumor should be recommended to see their regular doctor as soon as possible for a first evaluation.