Glomus tumor

Definition - What is a glomus tumor?

Glomus tumor refers to a specific, usually benign type of tumor. The term glomus originates from Latin and means " tangle ". Medically, it describes a collection of cells which produce and release different hormones directly into the blood.

They are part of the peripheral nervous system. Because these glomera are also referred to as paraganglia, another term for glomus tumors is paraganglioma.

There are several paraganglia in the body from which tumors might develop. Most important among these are the paraganglia of the middle ear and the carotid glomus (carotid body).

Around the middle ear, the glomus tympanicum and the glomus jugulare make up important paraganglia. These glomus tumors are among the most common tumors of the middle ear. and although they may not cause any pain, usually patients experience noises in the ear.

The carotid body is situated in the neck around the junction of the common carotid artery. This artery supplies parts of the head and brain with blood. Among other things, the cells of the carotid body play an important role in regulating the circulatory system as they measure the oxygen and carbon dioxide concentrations in the blood and release the appropriate compounds into the blood when there is a discrepancy. For example, the heart rate or output of the heart can be adjusted in this way.

Altogether, glomus tumors are classified as a rare disease. Females are more frequently affected than males, and it is only in very rare cases that a glomus tumor is diagnosed in children.

Causes - How does a glomus tumor develop?

Glomus tumors arise from various mutations, which are changes in the genetic material of the respective cells. However, the precise cause of the emergence of these mutations is still widely unknown.

But it is assumed that in about one third of all cases the disease runs in families, while in the remaining two thirds it happens more sporadically, in other words very rarely and with no apparent link to the family history.

As in almost all tumors, certain mutations can be found in paragangliomas, which allow the cell to grow and develop uncontrollably. This leads to excessive growth.

Benign tumors only affect the organism because of their size and the associated effect on adjacent structures. In contrast, malignant tumors undergo dysplasia, they damage adjacent organs and may spread throughout the body through the bloodstream or lymphatic system.

Luckily, the majority of paragangliomas are benign tumors.

Symptoms - How can a glomus tumor be noticed?

Most often, a glomus tumor is accidentally diagnosed during an ultrasound examination or another type of imaging in the neck area. Occasionally, patients may notice a painless swelling, which prompts them to see a doctor. There is usually no pain.

In the middle ear area, glomus tumors can produce noises in the ear that are synchronized with the pulse. This is because paragangliomas are well supplied by blood vessels and consequently have a lot of blood flow. At times, hearing loss or dizziness may also be experienced.

In rare cases, with very late detection of the tumor, there may also be bleeding from the ear due to damage and rupture of the eardrum caused by the tumor size.

In cases where the glomus tumor is located elsewhere than the middle ear, different symptoms may also occur. Among these are cranial nerve impairments or, as with a tumor located in the area of the carotid body, fluctuations in blood pressure.

Therapy - What are the treatment options?

There are several therapeutic options available for the treatment of a glomus tumor.

Surgical removal of the tumor is performed in most cases, as a smaller tumor size has been proven to have positive effects.

Often, prior to surgery, a so-called embolization is carried out. In this case, the blood flow to the tumor is interrupted by occluding the corresponding vessels. The growth of the tumor is thus hindered which in turn makes it easier to remove.

However, given that many paragangliomas arise in locations with difficult access, surgical removal can at times be challenging. Radiation therapy is a frequently used option for these cases. Through radiation exposure, cell division and consequently the growth of the tumors is inhibited.

Surgery - What is the procedure of glomus tumor surgery?

Glomus tumors represent a very diverse group of tumors with different localization and characteristics and this is why the surgical removal must always be adapted precisely to the disease and the patient's situation.

The operation can be performed in combination with previous embolization or radiotherapy, according to the size and localization of the tumor.

Since the blood supply to paragangliomas is very extensive, great care must be taken to avoid major bleeding during surgery. Depending on their location, tumors can be easier or harder to remove.

In case of a glomus tumor situated near the carotid body, there is a risk of a massive release of hormones during surgery. Because these hormones play an essential role in the regulation of the circulation, the respective receptors responding to these hormones must be blocked beforehand. This minimizes the risk of blood pressure abnormalities during surgery.

Following surgery, patients stay in the hospital for about three days. Once they have been discharged, patients will undergo regular follow-up visits. Approximately once every, an ultrasound examination is performed to check for possible tumor recurrence.

Prognosis - Course & chances of cure 

The prognosis for glomus tumors is largely determined by the type of tumor. The main determinant is whether the tumor is benign or malignant.

The majority of cases are benign tumors for which an early surgical removal of the tumor offers a favorable chance of cure. It should be kept in mind, however, that any benign glomus tumor is essentially able to turn malignant.

In approximately 35% of all cases, glomus tumors are malignant. In such cases, the tumor has metastasized to other organs. Not only does this complicate the therapy, it also decreases the chances of cure.

Unfortunately, it is not possible to provide any general statement regarding the chances of cure for this very rare and specific tumor.

Which doctors & clinics specialize in the diagnosis & treatment of glomus tumors?

A glomus tumors represent very rare disease which can present with many different characteristics, each treatment needs to tailored to the patient's individual needs. So-called tumor conferences host specialists from different medical fields to establish an individualized treatment plan for each patient.

The professional expertise of these physicians is crucial for the quality of the treatment.

We have reviewed all listed doctors accordingly and offer you the opportunity to get in touch with our experts here. This will ensure that you are provided with the highest quality treatment that meets the most recent scientific standards.

Sources:

• Amboss, Nachschlagewerk für Medizinier

• next.amboss.com/de/article/oj00YT

• Derrick L, Carty SE, Young Jr (2013) Paragangliomas: epidemiology, clinical presentation, diagnosis, and histology