retinoblastoma /ret′inōblastō″mə/ pl. retinoblastomas, retinoblastomata [L, rete + Gk, blastos, germ, oma, tumor] , a congenital hereditary neoplasm developing from retinal germ cells. Characteristic signs are diminished vision, strabismus, retinal detachment, and an abnormal pupillary reflex. The rapidly growing tumor may invade the brain and metastasize to distant sites. Treatment includes removal of the eye and as much of the optic nerve as possible, followed by radiation and chemotherapy. It is bilateral in about 30% of the cases. The more affected eye is enucleated, and the other eye is treated with radiation, antibiotics, cryotherapy, or photocoagulation, singly or in combination. Because many of the cases are transmitted as an autosomal-dominant trait with incomplete penetration, genetic counseling is advisable.
