Glomus Tumor (Head & Neck Paraganglioma), from the CureRays guide library.

Glomus tumors are usually benign, slow-growing tumors of the head and neck that wrap around blood vessels and nerves; focused radiation (radiosurgery) often controls them with less risk than surgery, and several occurring together can point to an inherited cause.

What it is.

A glomus tumor — more precisely a head and neck paraganglioma — is a tumor that grows from small clusters of specialized cells (paraganglia) that normally sit alongside blood vessels and nerves and help sense and regulate the body. In the head and neck these tumors form in a few characteristic spots: at the carotid artery in the neck (carotid body tumor), in the bone behind the ear near the hearing and balance structures (glomus tympanicum and glomus jugulare), and along the vagus nerve (glomus vagale). The great majority are benign, meaning they are not cancer and rarely spread, but they are locally important because they are highly vascular (full of blood vessels) and grow in crowded areas right next to major arteries, the hearing and facial nerves, and the nerves that control swallowing and the voice. As they slowly enlarge they can cause a pulsing sound in the ear, hearing loss, dizziness, a neck mass, hoarseness, or difficulty swallowing. A small minority release hormones (catecholamines) that can raise blood pressure and heart rate, which is checked for before any procedure because it changes how the tumor is handled. Two features shape modern care. First, because these tumors grow slowly and sit among delicate nerves and vessels, the goal is durable control with the least harm — and focused radiation has become a leading way to achieve that, often controlling the tumor without the nerve injury or major bleeding risk that surgery can carry. Second, a substantial share of head and neck paragangliomas are linked to inherited gene changes (most commonly in the SDHx genes), so finding one — especially several, or one at a young age — should prompt genetic counseling and screening for additional tumors elsewhere in the body.

How radiation treats it.

Radiation therapy controls glomus tumors by delivering focused energy that damages the DNA of the tumor cells and, over time, the rich network of blood vessels that feeds them, so the tumor stops growing. Because these tumors are usually benign and slow-growing, the aim of radiation is local control — stabilizing a tumor in its crowded location so it no longer threatens nearby nerves and vessels — rather than eradicating a spreading cancer. This is exactly why radiation has become so prominent for head and neck paragangliomas, particularly glomus jugulare tumors at the base of the skull. There, surgery sits among the lower cranial nerves that control swallowing, the voice, and the tongue, as well as the hearing and facial nerves, so an operation can carry a meaningful risk of lasting nerve injury and significant bleeding from the tumor's vascularity. Stereotactic radiosurgery offers an alternative that controls the great majority of these tumors while leaving those nerves intact: a high, sharply focused dose is delivered in one or a few sessions, conforming tightly to the tumor and falling off quickly at its edges to protect the surrounding structures. For larger tumors or those abutting especially sensitive areas, the dose can instead be divided over several treatments to further spare healthy tissue. The benefit develops gradually, over months to a couple of years, as the tumor's blood vessels close down and growth halts or the tumor slowly shrinks; lasting tumor control is achieved in roughly nine out of ten patients in long-term series, with low rates of new nerve problems. Radiation can also be used after surgery when a tumor cannot be completely removed. In the rare event that a paraganglioma is malignant and has spread, a different form of radiation — targeted radionuclide therapy such as MIBG or PRRT — can deliver radiation from inside the body to tumor deposits wherever they are. Embolization, which blocks the tumor's blood supply, is sometimes used before surgery, but is generally not needed when radiation is the chosen treatment. Overall, focused radiation gives these benign but awkwardly located tumors a durable, function-preserving form of control.

The ways we can treat it.

Stereotactic radiosurgery (SRS). Delivers a high, precisely shaped dose to the tumor in one or a few sessions, halting growth while sparing the adjacent hearing and balance structures, facial nerve, and lower cranial nerves — a favored approach for glomus jugulare tumors.

Fractionated stereotactic radiotherapy. Divides focused radiation over several treatments for larger tumors or those hugging especially sensitive structures, reducing the dose to nearby tissue per session while still controlling the tumor.

Targeted radionuclide therapy (for malignant disease). For the rare paraganglioma that spreads, treatments such as I-131 MIBG or peptide receptor radionuclide therapy (PRRT) deliver radiation from within to tumor cells that take up specific molecules, controlling disease throughout the body.

Questions we hear often.

Is a glomus tumor cancer? Almost always, no. The great majority of head and neck glomus tumors (paragangliomas) are benign — they grow slowly and rarely spread. They matter because of their location, wrapped around major blood vessels and the nerves that control hearing, the face, the voice, and swallowing. Only a small minority are malignant, defined by spread to lymph nodes or distant sites, and those are treated more aggressively.

Why might radiation be chosen over surgery? Many of these tumors sit at the skull base among delicate nerves, where surgery can risk lasting injury to swallowing, the voice, the face, or hearing, plus significant bleeding because the tumors are so vascular. Focused radiation (stereotactic radiosurgery) controls the tumor in about nine out of ten cases while preserving those nerves, so it is often preferred for glomus jugulare and other hard-to-reach tumors. Accessible tumors may still be best removed surgically.

Should my family be tested? Possibly. A significant share of head and neck paragangliomas are linked to inherited gene changes, most often in the SDHx genes — especially when there is more than one tumor, a young age at diagnosis, or a family history. Genetic counseling can clarify the risk, guide screening for additional tumors elsewhere in the body, and determine whether relatives should be tested.

This guide is informational only. It is not medical advice — please confirm anything here with your care team.