The diagnosis of retinoblastoma is ordinarily not difficult; the symptoms vary with the stage at which the disease is detected. Its early stages have only been observed in the less-involved eye of bilateral cases, consisting of a whitish gray prominent focus, single or multiple in the posterior part of the retina. According to the larger statistics reported in the literature, the peak of incidence of this tumor is in children between 2 and 3 years of age. In Wintersteiner's1 monograph, of 467 cases, less than 3% were 7 years old; in the series of Moorfields Hospital, Duke-Elder,2 with 163 cases, had an even smaller percentage of this age, and Dollfuss and Auvert,3 in a tabulation of 889 cases, noted only 1.6% for this age group.
As long as the disease is confined to the posterior segment of the eyeball the differential diagnosis is concerned with metastatic retinitis, Coats'
WEIZENBLATT S. Differential Diagnostic Difficulties in Atypical RetinoblastomaReport of a Case. AMA Arch Ophthalmol. 1957;58(5):699-709. doi:10.1001/archopht.1957.00940010719009