Glomus jugulare tumors develop from glomus bodies on top of the jugular bulb. The jugular bulb is a region or section of the jugular vein, which is a large vein that drains venous blood from the brain through the neck and into the heart. The jugular bulb is positioned immediately below the middle ear. So, glomus jugulare tumors start their growth under the middle ear. With time, glomus jugulare tumors will often grow into the bottom of the middle ear. Larger tumors may grow around the carotid artery in the skull and even grow into the brain. The symptoms of a glomus jugulare are similar to that of a glomus tympanicum including: pulsatile tinnitus, conductive or mixed hearing loss, ear pain and/or bleeding from the ear. Because of the complex anatomy around the jugular bulb, glomus jugulare tumors may also produce numerous other symptoms.
There are several cranial nerves (nerves that come directly off of the brain) that surround the jugular bulb. Glomus jugulare tumors may compress these nerves. If these cranial nerves are affected, then symptoms of facial weakness, hoarseness, difficulty swallowing, shoulder drooping and/or tongue weakness may develop. A small percentage of glomus jugulare tumors may also produce a large amount of an adrenaline-like hormone (norepinephrine). Norepinephrine can cause symptoms such as anxiety, headache, tremor, flushing, high blood pressure, and a rapid heart rate.
As with a glomus tympanicum, the diagnosis of a glomus jugulare tumor is made based on symptoms, physical findings, hearing tests and a CT of the ear/temporal bone. Physical examination may also show a reddish/bluish mass behind the ear drum (See figure). In the case of a glomus jugulare, the mass behind the ear drum is really just the “tip of the iceberg”. An MRI is also ordered to examine the size of the tumor in relationship to the surrounding soft tissue of the brain or blood vessels. Blood and urine tests are done to determine if the tumor is secreting adrenaline-like hormones. These “active” tumors are treated with special high blood pressure medications prior to surgery to prevent anesthetic complications.
Angiography (mapping out blood vessels by injecting dye directly into an artery under x-ray visualization) is performed to identify the blood vessels supplying the tumor. Angiography will also determine if the internal carotid artery or internal jugular vein is involved. Angiography also can be used to embolize (intentionally clot) the feeding vessels to decrease tumor bleeding during surgery.
Options for treatment include:
1. Complete microsurgical removal
2. Gamma Knife Radiosurgery
alone (This is recommended for elderly patients or patients in otherwise poor health)
3. Microsurgery and Gamma Knife Radiosurgery
(This option involves microsurgical removal of the portion of the tumor in the middle ear, followed by radiotherapy for the remainder of the tumor. Removal of the tumor in the middle ear is performed to help with the symptom of pulsatile tinnitus and to try to improve hearing. Both the microsurgical and radiosurgical procedures are outpatient procedures.)
Complete microsurgical excision of a glomus jugulare tumor requires more extensive surgery than that for glomus tympanicum tumors. This is an exciting time because advances in surgical technique, imaging technology, and interventional radiology over that past four decades have enabled the removal of previously unresectable tumors. Surgery is often performed through incisions extending from the scalp down into the neck. Sometimes the middle ear hearing bones are removed, which causes a partial hearing loss. Depending on the size of tumor, structures such as the jugular vein, carotid artery, cranial nerves, eustachian tube, and the temporomandibular joint (jaw joint) may be exposed. Large tumors may also require a craniotomy (exposing the brain) by a neurosurgeon to remove tumor touching the brain. Hospital stay is often several days when complete microsurgical removal is performed.