Paraganglioma: Causes, Symptoms, Diagnosis, and Management

Introduction

Paraganglioma is a rare and treatable condition. It is a neuroendocrine tumor formed in the neck and head's blood vessels and nerves. These tumors are benign. In sporadic cases, it is malignant. Symptoms caused by this condition are high blood pressure and headache. Paraganglioma is caused due to abnormal growth of nerve cells that are present throughout the body. These nerve cells, called chromaffin cells, are responsible for many functions.

What Is Meant by Paraganglioma?

Paraganglioma, also known as extra-adrenal pheochromocytoma, is a neuroendocrine tumor that occurs in the carotid artery, the significant blood vessel present in the neck and along the newer pathways present in the neck and other regions of the body. This tumor consists of a certain type of cell known as chromaffin cells. These cells synthesize and release hormones called catecholamines. The adrenal gland, which is located on top of the kidney, produces various hormones along with catecholamines, which are responsible for specific body functions such as:

• Heart rate.

• Blood pressure.

• Blood sugar.

• It regulates stress.

The primary catecholamines involve:

• Dopamine.

• Epinephrine.

• Norepinephrine.

Signs and symptoms are caused due to excess catecholamine in the blood caused by paraganglioma.

How Is Paraganglioma Different From Pheochromocytoma?

Both paraganglioma and pheochromocytoma tumors are caused by the same cells called chromaffin cells. The variation occurs in the region where they occur. Pheochromocytoma occurs in the center of the adrenal gland, whereas paraganglioma occurs in the nerves or arteries of the neck outside the adrenal gland.

Is Paraganglioma a Form of Cancer?

Paraganglioma is usually benign and is not cancerous, but in rare cases, it can be cancerous. About 20 % are cancerous. It is very tough for doctors to diagnose whether the formed tumor is benign or malignant, even after removal. Due to this, paraganglioma is considered to be cancerous if:

• Spread of this condition to nearby tissue.

• The spread of this condition to the lungs and bone is called metastasis.

• Recurred.

There is no proper staging for the cancerous form of paraganglioma, but it is described as:

• Localized Paraganglioma: The tumor is located in only one region.

• Regional Paraganglioma: When cancer spreads to lymph nodes and other tissues near the locations.

• Metastatic Paraganglioma: Cancer has spread to various body parts, such as the liver, lungs, bone, and lymph nodes. About 35 % to 50 % of the paraganglioma undergo metastasis.

• Recurrent Paraganglioma: It is when the treated cancer has recurred. It can occur in the same region or different body parts.

What Are the Signs and Symptoms of Paraganglioma?

The signs and symptoms of this condition occur when excess adrenaline or noradrenaline is released into the blood. However, it does happen on occasion even when too much noradrenaline or adrenaline does not result in any symptoms. Some common signs and symptoms of this condition are:

• Hypertension.

• Headaches.

• Excessive sweating.

• Fast or irregular heartbeat.

• Feeling shaky.

Very Rare Symptoms Are:

• Being much paler.

• Nausea and vomiting.

• Diarrhea.

• Constipation.

• Hyperglycemia, high glucose level.

• A sudden decrease in blood pressure on standing is called orthostatic hypotension.

• Weight loss.

What Is the Cause of Paraganglioma?

The exact cause of paraganglioma is not known. About 25 to 30 % affected with this condition have a hereditary condition that is associated with paraganglioma, which may include:

• Multiple endocrine neoplasia type 2 syndromes.

• Von Hippel-Lindau (VHL) condition.

• Neurofibromatosis type 1.

• Hereditary paraganglioma syndrome.

• Carney triad.

How Is Paraganglioma Diagnosed?

As paraganglioma is a rare condition and asymptomatic, it is challenging to diagnose. In rare cases, this condition is diagnosed during tests performed to find other medical conditions. The diagnosis of the condition is made after reviewing,

• Medical history, including past pheochromocytoma or paraganglioma cases in the family.

• A complete physical or mental examination.

• Specific symptoms like raised blood pressure, which is not responding to routine treatment.

Specific tests are performed for the diagnosis of paraganglioma. These are:

• Physical examination.

• 24-hour urine test.

• Blood catecholamine test.

• PET scan (positron emission tomography scan).

• CT scan (computer tomography).

• MRI (magnetic resonance imaging).

How Is Paraganglioma Managed?

The management of paraganglioma depends on,

• Size of the tumor.

• Depending on whether the tumor is benign or malignant.

• Symptoms that occur due to excessive catecholamines in the blood.

• Whether the tumor undergoes metastasis.

• If the tumor has occurred for the first time or recurred.

If paraganglioma is caused due to excessive adrenal hormone, then the doctors recommend certain medications, such as:

• Alpha-blockers, which regulate blood pressure.

• Beta-blockers regulate the normal heart rate.

• Medications that block the effects of the excessive hormone present in the blood.

The Various Treatment Option for Paraganglioma Includes

• Surgery or removal of the tumor.

• Radiation therapy:

  • External radiation therapy.

  • Internal radiation therapy.

• Chemotherapy.

• Ablation therapy.

  • Radiofrequency ablation.

  • Cryoablation.

• Targeted therapy.

Can Paraganglioma Be Prevented?

Paraganglioma cannot be prevented, but if the person is at risk of developing this condition due to an inherited syndrome of the gene, then genetic counseling can help. A consultation with the doctor regarding the first-degree relatives being affected by any conditions such as:

• Multiple endocrine neoplasia 2 syndromes.

• VHL condition.

• Neurofibromatosis type 1.

• Carney triad.

• Hereditary paraganglioma condition.

What Is the Prognosis of Paraganglioma?

The prognosis of this condition depends on:

• The location and size of the tumor.

• If the condition is malignant and has spread to other regions.

• If the tumor can be eliminated surgically.

What Are the Complications of Paraganglioma?

If paraganglioma is left untreated, whether benign or malignant, it can result in severe life-threatening conditions due to increased adrenaline or noradrenaline in the blood. Some common complications are:

• Cardiomyopathy - A heart muscle disease.

• Myocarditis - Heart muscle inflammation.

• Cerebral Hemorrhage - Uncontrolled bleeding in the head.

• Pulmonary Edema - A collection of fluid in the lungs.

• Heart attack.

• Coma.

Conclusion

Paraganglioma is a rare neuroendocrine condition where the cause is unknown, but there is a significant association with inherited conditions. The signs and symptoms of this condition are caused due to excessive adrenaline and noradrenaline in the blood. These tumors can be benign or malignant, depending on the cause; they are being treated through medications or other methods. These tumors usually occur in the arteries and blood vessels of the neck and are treatable.