Retinoblastoma is a malignant tumor of the retina, the membrane at the back of the eyeball. About 200 children in the United States develop this cancer each year, most diagnosed before they reach the age of five. The tumor may be in one eye (70 percent) or both eyes (30 percent).
How It Spreads The tumor may be confined to the retina or extend directly to other parts of the eye. In its later stages, it may spread to the central nervous system or other parts of the body.
What Causes It There are hereditary and non-hereditary forms of retinoblastoma. When there is disease in both eyes, it is almost always the hereditary form. The retinoblastoma gene has been identified and, therefore, families of children with retinoblastoma should have genetic counseling.
