Paragangliomas / Glomus Tumors of the Head and Neck
Paragangliomas are rare, neuroendocrine tumors that can involve different areas of the skull base and neck. Also known as “glomus” tumors, paragangliomas are named for the structures they arise from: carotid body tumors are the most common, followed by those involving a large vein called the jugular bulb (glomus jugulare), those involving the middle ear (glomus tympanicum), and finally the vagus nerve (glomus vagale).
Paragangliomas may occur at any age, though the majority are diagnosed between ages 40 and 60. Most paragangliomas occur in isolation, but 3-10% of patients can have multiple tumors. Up to 40% of paragangliomas arise from heritable genetic mutations, the most common of which involve the succinyl dehydrogenase gene. A few tumors are associated with other neuroendocrine diseases such as neurofibromatosis type 1, multiple endocrine neoplasia type 2, von Hippel-Lindau disease.
Less than 10% of paragangliomas from the head and neck are malignant and able to spread to other locations. The majority are benign and show no spread or metastasis.
Paragangliomas arising from the carotid body or vagus nerve may present as a painless neck mass. On the other hand, because of their association with the middle ear, glomus jugulare and glomus tympanicum tumors more commonly present with pulsatile tinnitus, hearing loss, and otalgia. These tumors can sometimes be seen on a doctor’s exam as a red mass behind the ear drum.
Depending on their location, tumors can also cause deficits of the cranial nerves. This can result in facial weakness, hoarseness, difficulty swallowing, tongue weakness, shoulder weakness, or a drooping eyelid. In 1-3% of patients with a paraganglioma involving the temporal bone, the tumor secretes hormones that can cause high blood pressure, elevated heart rate, or episodic sweating and anxiety.
A patient’s history, physical examination, and imaging studies are used in the diagnosis of vestibular schwannoma. A CT or MRI with and without contrast are often used to show the location and size of these highly vascular tumors. Angiography can demonstrate the tumor’s relation to blood vessels. A catecholamine urine and/or blood test may be used to assess whether the tumor secretes hormones. If multiple tumors or a related pheochromocytoma tumor in the abdomen are suspected, specialized nuclear medicine images such as an “octreotide scan” may be ordered.
Treatment decisions are informed by the patient’s symptoms such as pulsatile tinnitus or neurologic deficits, the growth, size, and location of the tumor, whether multiple tumors are present, and the patient’s general medical condition. The patient and physician team collaborate together to determine the best path to optimize quality-of-life and tumor control.
- Monitoring – Some patients are monitored with repeated imaging and physical exams.
- Surgery – The extent of surgery depends on the tumor location. For example, surgery for glomus tympanicum might only involve a short, outpatient procedure. On the other hand, surgery for a larger glomus jugulare might require a postoperative stay in the ICU. Surgery is sometimes performed in conjunction with embolization, which is a procedure that decreases the blood supply to the tumor.
- Stereotactic Radiation – A computer-guided delivery system is used to deliver highly focused beams of x-ray radiation to the tumor, while minimizing effects to the surrounding tissue. While radiation does not remove the tumor, it can be effective in stopping the growth of a tumor.
- Combination of the above
Multiple views of a glomus tympanicum, which is a paraganglioma involving the middle ear. In this case the tumor abuts the small hearing bones known as the ossicles, causing hearing loss and the sound of a heartbeat in the ear.
Multiple views of a glomus jugulare, which is a paraganglioma involving the jugular bulb. These tumors can cause deficits of the facial or lower cranial nerves in addition to hearing loss and the sound of a heartbeat in the ear. The arrows indicate a typical growth pattern, with extension up into the middle ear, and along the course of the jugular vein.