<prompt> Retinoblastoma is bilateral in100 of cases1 of cases50 of cases30 of cases  <response>: Retinoblastoma: It is a malignant glioma of the retina, usually unilateral, that occurs in young children and usually is hereditary. In about 30 of patients retinoblastoma is bilateral. The initial diagnostic finding is usually a yellow or white light reflex seen at the pupil cats eye reflex. 