- A malignant eye tumor caused by the loss of a pair of tumor-suppressor genes. An inherited form of retinoblastoma (it typically appears at birth, leads to multiple tumors and affects both eyes) is due to a transmissible (germline) mutation followed by an acquired (somatic) mutation. The sporadic form of retinoblastoma (it has later onset and leads to a single tumor in one eye) is due to acquired (somatic) mutations of both tumor-suppressor genes. When the tumor is detected at an early stage, it can sometimes be treated locally, but it often unfortunately requires removal of the eye (enucleation).
* * *Malignant ocular neoplasm of childhood, with onset usually before the third year of life, composed of primitive retinal small round cells with deeply staining nuclei and elongated cells forming rosettes; there is an increased risk of developing osteosarcoma later in life. In familial cases, the disease is usually bilateral with multiple lesions within an eye, but in sporadic cases rarely so. Autosomal dominant inheritance caused by mutation in the tumor-suppressor r. gene (RB) on chromosome 13q. [retino- + G. blastos, germ, + -oma, tumor]
* * *ret·i·no·blas·to·ma .ret-ən-ō-.blas-'tō-mə n, pl -mas also -ma·ta -mət-ə a hereditary malignant tumor of the retina that develops during childhood, is derived from retinal germ cells, and is associated with a chromosomal abnormality
* * *n.a rare malignant tumour of the retina, occurring in infants.
* * *ret·i·no·blas·to·ma (ret″ĭ-no-blas-toґmə) [retina + blastoma] a malignant, often congenital blastoma, occurring in both hereditary and sporadic forms, composed of tumor cells arising from embryonic retinal cells. it appears in one or both eyes in children under 5 years of age, and is usually diagnosed initially by a bright white or yellow pupillary reflex (leukokoria). It is caused by germline or somatic mutations, or both, in both alleles of the retinoblastoma (RB1) gene. Called also glioma retinae.
Medical dictionary. 2011.