Epithelioid Hemangioendothelioma, from the CureRays guide library.

Epithelioid hemangioendothelioma is a rare cancer of the cells that line blood vessels, often appearing in the liver, lungs, or bone as several spots at once; its pace varies widely — from years of stability that may only need watching to disease that needs treatment — so care is individualized, with radiation used to control specific painful or problem areas.

What it is.

Epithelioid hemangioendothelioma (EHE) is a rare cancer that arises from endothelial cells — the cells that line the inside of blood vessels. Because blood vessels run throughout the body, EHE can begin almost anywhere, but it most often appears in the liver, the lungs, the bones, and the soft tissues. A distinctive feature is that it frequently shows up as several spots at the same time within an organ — for example, multiple nodules scattered through the liver or both lungs — which can make it look like a cancer that has spread when in fact it is the way EHE typically presents. EHE is defined by a specific genetic change, most commonly a fusion of two genes called WWTR1 and CAMTA1, which can be confirmed on a biopsy and helps distinguish it from other vascular tumors. EHE is considered an 'intermediate' cancer: it is more serious than a benign growth but generally less aggressive than a high-grade sarcoma, and — unusually — its behavior varies enormously from person to person. In some people it stays stable for many years with no treatment at all, while in others it grows steadily or causes symptoms such as pain, and a smaller group have a more aggressive course. Because of this variability, there is no single treatment that fits everyone. Management is tailored to how the disease is behaving and may range from careful observation, to surgery for a single removable tumor, to systemic medicines for widespread or progressing disease — with radiation used to control specific tumors that are painful, growing, or threatening an important structure.

How radiation treats it.

Radiation therapy treats epithelioid hemangioendothelioma by delivering precisely aimed beams of energy that damage the DNA inside tumor cells so they can no longer grow and divide. Because EHE is an unusual cancer that often appears in several places at once and varies so much in pace, radiation is generally used in a targeted, problem-solving way rather than as a single treatment for the whole disease. Its most common role is local control of a specific tumor that is causing trouble — a deposit in a bone that is painful or threatening a fracture, a growing nodule pressing on an important structure, or a spot that is enlarging while the rest of the disease remains quiet. Focused radiation can shrink or stabilize such a tumor and relieve the symptoms it causes, often with a relatively short course. In the bone in particular, radiation is frequently the main local treatment because surgery there can be difficult. Radiation is also used after surgery in selected cases — when a single tumor has been removed but the margin is close — to sterilize any microscopic disease left at the edges and lower the chance of it returning. For a limited number of nodules in the lung, liver, or bone, stereotactic body radiation can deliver a concentrated, ablative dose to each spot while sparing surrounding tissue, an approach that fits EHE's tendency to grow slowly and appear in just a few sites. Importantly, because many people with EHE have disease that stays stable for years, radiation is reserved for tumors that genuinely need it; treating every spot regardless of behavior would add side effects without benefit. Throughout, modern planning shapes the dose tightly around each target so that nearby healthy organs — the liver, lungs, and bone marrow — are spared as much as possible.

The ways we can treat it.

Definitive radiation for bone tumors. Focused radiation controls EHE in the bone, relieving pain and reducing the risk of fracture, and is often the main local treatment when surgery isn't practical.

Postoperative (adjuvant) radiation. Radiation to the tumor bed after surgery sterilizes microscopic disease left behind, lowering the chance of recurrence when margins are close.

Stereotactic body radiation (SBRT). Focused, high-dose beams can ablate a limited number of nodules in the lung, liver, or bone without surgery, providing durable control of isolated problem spots.

Palliative radiation. A short course of radiation can quickly relieve pain or other symptoms from a specific tumor, improving comfort and quality of life.

Questions we hear often.

My scan shows several tumors — does that mean my cancer has already spread? Not necessarily, and this is one of the most important things to understand about epithelioid hemangioendothelioma. Because EHE arises from the cells that line blood vessels, it commonly appears in multiple spots within an organ — such as several nodules through the liver or both lungs — right from the start. This multifocal pattern is the way the disease often shows up, not proof that it is rapidly spreading. What matters more is how those spots behave over time: whether they are stable or growing, and whether they are causing symptoms. That is why a period of close observation with repeat scans is sometimes the wisest first step, even when several tumors are present.

Why might my doctor recommend watching the cancer instead of treating it right away? Because EHE is unusual in how variable it is. In many people it stays stable for years and may never need active treatment, while in others it grows and does. Since the only reliable way to tell which course a person's disease will take is to watch it over time, careful surveillance with repeat imaging is often the most informative — and safest — first approach when the disease isn't growing or causing symptoms. This avoids the side effects of treatments that may not be needed. If the disease does begin to progress or cause problems, treatment can start then, targeting the specific tumors that need it.

When is radiation used for epithelioid hemangioendothelioma? Radiation in EHE is usually targeted at a specific tumor that is causing or threatening a problem rather than at the whole disease. The most common use is for a deposit in a bone that is painful or at risk of fracturing, where focused radiation controls the tumor and relieves pain. It is also used after surgery in selected cases to lower the chance of a removed tumor returning, and — for a small number of nodules in the lung, liver, or bone — stereotactic body radiation can deliver a concentrated, ablative dose to each spot. Because much EHE stays stable, radiation is reserved for tumors that genuinely need it rather than applied to every spot.

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