Hemangioblastoma, from the CureRays guide library.

Hemangioblastomas are benign, blood-vessel-rich tumors of the brain, brainstem, or spinal cord; many are cured by surgery, focused radiosurgery controls those that are hard to reach, and finding several can point to the inherited VHL syndrome.

What it is.

A hemangioblastoma is a benign (non-cancerous) tumor made up of a dense tangle of small blood vessels. It almost always grows in the central nervous system — most often in the cerebellum (the part of the brain at the back of the head that controls balance and coordination), but also in the brainstem and spinal cord. Although it is not cancer and does not spread to other organs, it matters because of where it grows: even a small tumor in these delicate areas can press on vital structures or block the flow of spinal fluid, causing headaches, balance problems, weakness, or numbness. Many hemangioblastomas also have a fluid-filled cyst attached to them, and it is often the cyst, expanding over time, that produces symptoms. A defining feature is the tumor's rich blood supply, which both gives it a characteristic appearance on scans and makes surgery technically demanding. Hemangioblastomas come in two settings. Most are sporadic — a single tumor in someone with no underlying condition — and removing it usually cures the problem. But about a quarter to a third occur as part of an inherited condition called von Hippel-Lindau (VHL) disease, in which people develop multiple hemangioblastomas over their lifetime along with tumors and cysts in other organs such as the kidneys, adrenal glands, and pancreas. Because of this, finding a hemangioblastoma — especially more than one, or one at a young age — should prompt a conversation about genetic testing and screening for the rest of the body. Treatment centers on surgery when the tumor is causing symptoms and can be safely reached, with focused radiation (radiosurgery) for tumors that are deep, multiple, or otherwise difficult to remove.

How radiation treats it.

Radiation therapy treats hemangioblastomas by delivering precisely focused energy that damages the tumor cells and, over time, the abnormal blood vessels that make up the tumor, halting its growth. Because hemangioblastomas are benign and do not spread, the goal of radiation is local control — stopping a specific tumor from enlarging and causing pressure on the brain, brainstem, or spinal cord — rather than treating the whole body. The treatment of choice for a symptomatic, reachable tumor is surgery, which can be curative. Radiation steps in when an operation is too risky or impractical: tumors deep in the brainstem, tumors wrapped around delicate structures, or the multiple tumors that develop in people with von Hippel-Lindau disease, where repeated open surgeries would be undesirable. The main technique is stereotactic radiosurgery, which concentrates a high, sharply defined dose on the tumor in one or a few sessions while sparing the surrounding normal tissue; for tumors next to especially sensitive areas the dose can instead be divided over several treatments, and for spinal tumors a focused spinal radiation approach is used. The benefit of radiation builds gradually over months to a couple of years as the tumor's blood vessels close down and it stops growing or slowly shrinks. One nuance is that the cyst frequently attached to a hemangioblastoma may respond more slowly than the solid tumor, and surgery remains better when a large cyst is the main source of symptoms. For people with VHL disease, radiosurgery is especially valuable because it allows several tumors to be controlled over a lifetime with minimal disruption, and it is increasingly combined with newer targeted medicines that shrink VHL tumors throughout the body. Used in the right situations, focused radiation offers durable control of these tumors while protecting the precious surrounding tissue.

The ways we can treat it.

Stereotactic radiosurgery (SRS). Delivers a high, precisely shaped dose to the tumor in one or a few sessions, controlling growth while sparing the surrounding brain or spinal cord — ideal for small, deep, brainstem, or multiple tumors.

Fractionated stereotactic radiotherapy. Spreads focused radiation over several treatments for tumors close to especially sensitive structures, lowering the dose to nearby healthy tissue per session.

Spinal stereotactic body radiation (SBRT). Focused radiation to a spinal cord hemangioblastoma that can't be safely removed, giving durable control while respecting the cord's dose limits.

Questions we hear often.

Is a hemangioblastoma cancer? No. A hemangioblastoma is a benign tumor — it is not cancer and does not spread to other organs. It matters because of where it grows: in the brain, brainstem, or spinal cord, where even a small tumor or its attached cyst can press on important structures and cause symptoms. Treatment is aimed at controlling that one tumor, not at fighting a spreading disease.

Why might I be tested for von Hippel-Lindau disease? Because a sizable share of hemangioblastomas — especially when there is more than one, when they appear at a young age, or when there's a family history — are part of an inherited condition called VHL disease. Diagnosing VHL matters because it means watching for new tumors over time and screening other organs such as the kidneys, adrenal glands, pancreas, and eyes, and offering testing to relatives.

When is radiation used instead of surgery? Surgery is the first choice for a symptomatic tumor that can be safely reached, and it is often curative. Focused radiation (stereotactic radiosurgery) is preferred when a tumor is deep, in the brainstem, or one of several tumors in VHL disease, where repeated operations would be undesirable. Radiation controls the tumor gradually over months while protecting the surrounding brain and spinal cord.

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