retinoblastoma

Definition of retinoblastoma
National Cancer Institute

retinoblastoma

(REH-tih-noh-blas-TOH-muh)
Cancer that forms in the tissues of the retina (the light-sensitive layers of nerve tissue at the back of the eye). Retinoblastoma usually occurs in children younger than 5 years. It may be hereditary or nonhereditary (sporadic).

Source: NCI Dictionary of Cancer Terms