Glomus Tumors (Paraganglioma)
Glomus tumors, also known as paragangliomas, are uncommon benign tumors that arise from the chemical receptor cells in the ear and skull base. These tumors typically grow slowly over time.
What are the Symptoms?
The most common symptoms include hearing loss and pulsating tinnitus (sounds) on one side. The hearing loss typically worsens slowly over time. Some patients also develop imbalance or spinning dizziness (vertigo). In more advanced cases, there can be chronic headache, hoarseness, difficulty swallowing, shoulder weakness, and difficulty with tongue motion.
What is the Evaluation Process?
Patients with a suspected glomus tumor undergo a full ear nose and throat evaluation in addition to testing such as audiogram and imaging such as MRI and/or CT. Based on the medical evaluation, the treatment options for the glomus tumor will be presented to you.
Figure 1 Glomus tumor of the right ear.
Figure 2 CT scan showing glomus tumor of the left ear.
What are the Treatment Choices?
There are various treatments for glomus tumor. The factors that help determine the best course of action depend on the patient’s age, health status, tumor size, nature and degree of symptoms, and patient preference.
Since many of these tumors grow slowly over time, small tumors may be observed for some time without treatment.
Stereotactic radiosurgery has been used for many years in this country. There are various ways to provide this radiation treatment, including gamma knife, linear accelerator, and cyber knife. In most cases, the radiation is provided in a single dose as an out-patient. The treatment does not result in tumor removal but the tumor growth can be arrested for many years. Depending on the size of the tumor, the swallowing, voice, and shoulder function can often be preserved, but may decline over time. The facial nerve can be injured as a result of treatment but the risk of injury is very low.
The tumor can be removed using various skull base approaches, depending on the size of the tumor and level of hearing. Complete tumor resection usually results in cure, but large tumors may not be able to be removed completely. The surgery for smaller tumors consists of an out-patient procedure such as tympanoplasty with or without mastoidectomy. For larger tumors, an infratemporal fossa skull base resection which includes surgery on the neck may be needed. In these cases, in-patient hospitalization is needed for 1 to 2 days. Larger tumors can bleed significantly during surgery and may require blood transfusions. In these cases, the tumor is treated with a procedure called embolization prior to the surgery. During this procedure, a catheter is inserted into the blood vessels that go to the tumor and these vessels are plugged up in order to reduce bleeding during surgery. The hearing function can be saved in many cases, depending on the tumor size. The facial nerve function is usually preserved for small to medium size tumors. The swallowing, voice, and shoulder function is typically preserved but may be significantly affected after surgery for large tumors.
After Surgery Care
Most patients can resume most normal daily activities after discharge from the hospital. Some patients develop significant dizziness after surgery requiring balance exercise therapy, or swallowing difficulty that may require swallowing therapy and occasionally a temporary feeding tube. Most patients resume regular work within a week to a month depending on the size of the tumor.
There is a small recurrence rate after tumor treatment that can become apparent many years after surgery. Patients should undergo periodic evaluation with MRI whether observation or treatment is chosen. There is a risk of significant hearing loss on the side of treatment if the hearing bones were affected by the tumor. This condition can be corrected with a reconstructive procedure called ossicular chain reconstruction that is performed either at the time of initial surgery or at a later date.