Glomus tumor

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at November 19, 2016
StartDiseasesGlomus tumor

Glomus tumors or paragangliomas are benign tumors arising from glomus cells or specialized nerve cells called paraganglia. As glomus cells can be found in the dermal layer of the skin and paraganglia found throughout the body, glomus tumors can effect a wide variety of symptoms. Treatment and management of these symptoms as well as the glomus tumors themselves are fairly straightforward, and individuals suffering from glomus tumors are generally minimally impacted by their development.

Contents

Definition & Facts

Glomus tumors are defined as benign tumors arising from the dermis layer of the skin. They usually form beneath a fingernail, on a finger, or on the foot. Glomus tumors are believed to be growths of smooth tissue cells that govern the thermoregulation of glomus bodies in the skin. 

These growths are slow-growing and benign, but also highly vascular and long-lasting. They are able to impact small areas of the body and occasionally produce hormones. Glomus tumors can also be found in the head and neck. Although these growths remain benign (noncancerous), they are considered to be locally invasive and are generally removed via surgery.

Symptoms & Complaints

Glomus tumors are slow-growing and benign and generally do not impact individuals' life expectancy or quality of life. However, complications do arise and require particular attention.

The vast majority of glomus tumors are found in the distal extremities as small, solitary lesions. Although they are generally found in the hand, foot, or under the fingernails, glomus tumors have been reported to have been found in areas of the body that do not normally contain glomus cells.

These small lesions are found most often in adults aged 20-40 and are identifiable by white or blue discolorations on the skin. Glomus tumors found under the nail can often raise the nail bed as well.

Glomus tumors arising in the head and the neck present more complicated symptoms depending on the extent and location of the growth. Growths in and near the tympanic membrane can cause ringing in the ears (tinnitus), hearing loss, and ear pain. Bleeding from the ear is another common symptom. 

Glomus tissue is also found in the deep neck tissue and can affect cranial nerve function, leading to a dropped shoulder or facial weakness.

Causes

Research has demonstrated the glomus tumors are caused primarily by genetic mutations identified at four distinct locations. Individuals with any of these four mutations are at a much higher risk than usual for developing glomus tumors. Sporadic growth in individuals without these genetic factors is also fairly common, though the root cause has yet to be discovered.

Glomus tumors growth is also spurred on by low oxygen levels, so individuals living at high altitudes are particularly susceptible to their development. The exact incidence of glomus tumors is unknown. The multiple variant is rare, accounting for less than 10 percent of all cases. The probable misdiagnosis of many of these lesions as hemangiomas or venous malformations also makes an accurate assessment of incidence difficult.

Diagnosis & Tests

Glomus tumors are usually first diagnosed during routine physical examinations by a primary care provider. The physician will usually confirm the diagnosis with questions about possible symptoms followed by imaging studies and a possible biopsy.

Individuals can often also observe dermal glomus tumors as blue or white discolorations on their hands, feet, or fingernails. Glomus tumors appearing in the ear can also be seen through otoscopy as a reddish mass just behind the eardrum. Being a part of a routine checkup, these are found relatively easily.

Computed tomography (CT) scans or magnetic resonance imaging (MRI) scans are standard in confirming paraganglioma and appears as a small of soft tissue. However, it can sometimes be difficult to distinguish between paraganglioma and abnormal carotid arteries or other abnormal masses. 

Ultimately, a biopsy might be necessary to completely confirm paraganglioma before moving on to the treatment phase. The process of obtaining a biopsy, however, is so involved that it is generally not considered as an option.

Treatment & Therapy

Most glomus tumors are benign and require little or no treatment. Generally, paraganglioma are observed carefully through scheduled scans and doctors' visits where the growth and location of the tumor is monitored for possible changes.

If a mass is determined to be harmful and must be removed, minimally invasive surgery is usually enough as treatment. Masses appearing behind the tympanic membrane are usually excised through the ear canal for a low risk procedure that requires minimally healing and no external scar.

For masses appearing in the jugular bulb, however, the procedure becomes slightly more complicated. Surrounded by cranial nerves and major blood vessels, these masses must be removed through the neck and pose risks of facial paralysis and damage to the nervous system.

Another option for treatment is radiation therapy. Radiation therapy cannot kill a glomus tumor, but it is able to prevent its growth enough for symptoms to either stop or be lessened. Current research is looking into saturating the body with oxygen, as a high level of oxygen appears to suppress the growth of glomus tumors, but this treatment has yet to be developed and applied to the general public.

Prevention & Prophylaxis

Ultimately, there is little individuals can do to prevent glomus tumors. Chances of developing these masses is determined primarily by genetics, and certain individuals are born with at much higher risk of developing these relatively benign tumors.

It has been shown that in individuals genetically predisposed to developing glomus tumors that living at high altitudes exacerbates the risk of developing them, so moving to locations with greater oxygen saturation may lower the chances of developing a glomus tumor.

Otherwise, prevention is generally impossible, but catching a glomus tumor has advantages and allows for a wider range of treatments. It is therefore important to note symptoms associated with glomus tumors as well as undergoing regular physical examinations with a family doctor familiar with the disease, particularly if one has a family history of glomus tumors.