Choroid Plexus Tumors, from the CureRays guide library.

Choroid plexus tumors grow from the tissue that makes the brain's fluid; most are curable with surgery alone, while the aggressive carcinoma form also needs chemotherapy and carefully shaped radiation to protect a child's developing brain.

What it is.

Choroid plexus tumors begin in the choroid plexus, the delicate, frond-like tissue inside the fluid-filled spaces of the brain (the ventricles) that produces cerebrospinal fluid — the clear liquid that cushions the brain and spinal cord. These tumors are rare and occur most often in infants and young children, though they can appear in adults. Because they grow inside the ventricles and the choroid plexus normally makes fluid, these tumors can cause too much fluid to build up, raising pressure inside the head. In babies this can make the head grow too quickly, while older children may have headaches, nausea and vomiting, sleepiness, or balance problems. There are three main forms that differ greatly in behavior: a benign papilloma, a borderline atypical papilloma, and a cancerous carcinoma. The papilloma is the most common and, once fully removed by surgery, is usually cured. The carcinoma is far more aggressive, can spread through the cerebrospinal fluid, and needs additional treatment. Because most patients are very young children whose brains are still developing, the central challenge is to cure the tumor while protecting long-term thinking, growth, and quality of life — which makes the choice and precision of treatment especially important.

How radiation treats it.

Radiation therapy uses precisely aimed high-energy beams to damage the DNA inside tumor cells so they can no longer grow and divide. For choroid plexus tumors, radiation's role depends entirely on which type a child has. A benign papilloma that is fully removed usually needs no radiation at all. The aggressive carcinoma is a different story: even after surgery and chemotherapy, radiation is often important to control the disease, particularly in children old enough to receive it safely. When the carcinoma is localized, radiation is shaped tightly around the tumor area; when it has spread through the cerebrospinal fluid, the entire brain and spine may be treated at a lower dose with a focused boost to the main site. Because most patients are very young, protecting the developing brain is a central concern. Modern planning with intensity-modulated radiation and, where available, proton therapy makes it possible to deliver an effective dose while sparing healthy tissue — protons are especially useful because the beam stops at a set depth and does not travel beyond the target. In the youngest children, doctors may delay or reduce radiation and lean on surgery and chemotherapy first, allowing the brain to mature before radiation is considered. The radiation oncologist tailors every plan to cure the cancer while protecting long-term thinking, growth, and quality of life.

The ways we can treat it.

Focused (conformal) radiation to the tumor bed. For a localized carcinoma, radiation is shaped tightly around the area where the tumor was, delivering an effective dose while sparing as much healthy, developing brain as possible.

Craniospinal irradiation when the tumor has spread. If cells have seeded the cerebrospinal fluid, the entire brain and spinal cord are treated at a lower dose, with a focused boost to the main tumor area.

Proton therapy. Proton beams deposit their energy and then stop, so they can treat the tumor while sparing nearby healthy brain and, when treating the spine, the organs in front of it — especially valuable for protecting a young child's development.

Age-adapted, delayed, or reduced radiation. In infants and toddlers, teams may rely on surgery and chemotherapy first to postpone or limit radiation until the brain is more developed, lowering the risk of long-term effects.

Questions we hear often.

Is my child's tumor cancer? Not always. The most common choroid plexus tumor is a benign papilloma, which is usually cured by surgery alone. The carcinoma form is cancerous and aggressive and needs additional treatment. A pathologist determines which type it is after surgery, and that answer guides the entire plan.

Will my young child need radiation? It depends on the type and the child's age. A fully removed papilloma usually needs no radiation. For the carcinoma, radiation is often important, but in infants and toddlers doctors may delay or limit it — relying on surgery and chemotherapy first — to protect the developing brain, and use proton therapy when available to spare healthy tissue.

Why is genetic testing recommended? Choroid plexus carcinoma is often linked to an inherited cancer-predisposition syndrome. Genetic counseling and testing can explain why the tumor developed, guide follow-up for the child, and identify other family members who may benefit from screening.

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