Snowball opacity in retinoblastoma.

From 1933 through 1980, 207 retinoblastoma patients were treated in our department. Recently, both hereditary and bilateral cases have increased in number, as some of the patients have borne children. Nine out of 87 patients in the last 16 years have had large snowballs in the vitreous or in the anterior chamber. We reported herein findings in two retinoblastoma patients, aged 14 and 17 years. In the first case the possibility of retinoblastoma was less likely to be considered because of the patient's age, but conclusive diagnostic findings were provided by ultrasonography and CT scan as well as by demonstration of a snowball in the anterior chamber. The second case was one of retinoblastoma that occurred 15 years after irradiation. The patient had been on a combination of radiotherapy and cryotherapy, and her eye had to be enucleated 17 months later because of the appearance of snowball opacities in the vitreous. We conclude that snowballs in the anterior chamber and the vitreous may provide an important clue as to the diagnosis and treatment of retinoblastoma.