Endocrine diseases

Pheochromocytoma

Endocrine diseases
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Pheochromocytoma
foto de Fernando Martínez Sáez
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Fernando Martínez Sáez
Medically reviewed by our Medical staff

Last update: 08-07-2021

How else can it be called?

  • Adrenal medullary tumor

  • Tumor of the adrenal medulla

  • Chromaffin tumor

  • CIE-9: 227.0

  • CIE-10: D35.0

What is a pheochromocytoma?

A pheochromocytoma is an endocrine tumor located in the adrenal glands that releases abnormal amounts of catecholamine hormones.

This type of tumor arises from chromaffin cells (also called pheochromocytes) present in the adrenal medulla.

The adrenal medulla is located in the center of the adrenal glands (also known as suprarenal glands) and they produce catecholamines, hormones derived from the amino acid tyrosine. Catecholamines, such as epinephrine (adrenaline) and norepinephrine (noradrenaline), are hormones released in response to physical and emotional stress.

About 10% of pheochromocytomas are bilateral (they are found in both adrenal glands at the same time). In children, the percentage of bilateral pheochromocytoma is much higher and can be present in the 37.5% of the cases.

A pheochromocytoma is commonly a benign tumor. Only 10% are malignant (as defined by the presence of metastases). They are usually found in the adrenal medulla, but it can also be found in the sympathetic ganglia or outside the adrenal glands. When the tumor is located outside the adrenal gland, it is called paraganglioma and the possibility of being malignant is higher (up to 25%).

What can cause a pheochromocytoma?

The causes for this tumor are still unclear. A small percentage of pheochromocytomas (around 25%) can be associated with genetic conditions, such as von Hippel-Lindau syndrome, MEN (Multiple Endocrine Neoplasia) syndrome or type 1 neurofibromatosis.

The most commonly mutated genes are:

  • RET (chromosome 10, 10q11.21) which can cause type 2 MEN (Multiple Endocrine Neoplasia).
  • NF1 (chromosome 17, 17q11.2) related to with type 1 neurofibromatosis.
  • VHL (chromosome 3, 3p25.3) which causes von Hippel-Lindau disease.
  • SDHB (chromosome 1, 1p36.1), SDHC (chromosome 1, 1q23.3), and SDHD (chromosome 11, 11q23.1) related to the enzyme succinate dehydrogenase complex.

What is the incidence of pheochromocytoma?

The incidence of this type of tumor is about 2 to 8 cases per 1 million people. Additionally, 0.1% of people with high blood pressure is as a consequence of a pheochromocytoma.

The mean age at diagnosis is from 40 years to 60 years old, although the tumors can occur from early childhood until late in life.

The pheochromocytoma has a higher incidence in the right adrenal gland than in the left (ratio 2:1).

What are the most common symptoms?

The main symptom is high blood pressure (hypertension), found in 60% of patients. Approximately two-thirds demonstrate paroxysmal hypertension (sudden rise in blood pressure and palpitations).

The most common symptoms include:

  • High blood pressure or hypertension (10% of patients may not have it).
  • Headache
  • Diaphoresis (excessive and abnormal sweating)
  • Palpitations and tachycardia (rapid heart rate)
  • Chest pain
  • Nausea and vomiting
  • Pallor
  • Anxiety and panic attacks

How can it be diagnosed?

The best way to diagnose a pheochromocytoma is to perform a 24-hour urine test. This test is useful to study the amount of free catecholamines (noradrenaline and adrenaline) and their metabolites (vanillylmandelic acid and metanephrines) in the urine. In case of suffering from a pheochromocytoma, these hormones will be elevated.

Catecholamines may also be studied through a blood test. The most sensitive test to diagnose a pheochromocytoma is the level of metanephrine in a blood test.

Another test that may be performed is the clonidine suppression test. Clonidine usually lowers the level of catecholamines in a healthy person, but they remain high in patients with pheochromocytoma.

The tumor may also be located and evaluated using other diagnostic tests such as CT (computerized tomography), MRI (magnetic resonance imaging) or scintigraphy.

How can be treated?

The recommended treatment is the surgical resection of the tumor by laparoscopic surgery. Alpha-blockers (oral Phenoxybenzamine) and beta-blockers (Propranolol) may be used before and after the surgery to control the high blood pressure (hypertension).

Other antihypertensive drugs can also be used such as calcium channel blockers and angiotensin- converting enzyme inhibitors (ACE inhibitors).

Postoperative follow-up is necessary. A blood or urine test should be performed 4 to 6 weeks after the surgery to monitor that the catecholamine levels have returned to the normal range. Subsequently, an annual catecholamine test is recommended to detect a possible tumor recurrence.

Medically reviewed by our Medical staff on 08-07-2021

Bibliography

  • Harrison’s Hematology and Oncology. Dan L. Longo. 3rd edition. 2017. ISBN: 978-1-25-983582-7. Pag 700.
  • Robbins Basic Pathology. 10th Edition. Vinay Kumar, Abul K. Abbas, Jon C. Aster. 2018. ISBN: 978-0-323-35317-5 Pag. 793
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