The topography of bilateral retinoblastoma lesions

The anatomic location of intraocular retinoblastoma foci was investigated in patients with bilateral retinoblastoma. The study was designed to evaluate the retinal topography of intraocular tumors and their time course of presentation. A retrospective study of 565 eyes with bilateral retinoblastoma was conducted. Data included patient age at detection of each tumor and tumor location within the retina. Intraocular location was characterized in three ways: 1) superior versus inferior retina; 2) nasal versus temporal retina; and 3) macular to peripheral retina, defined as four circular zones. There was a direct correlation between patient age at tumor detection and retinal topography. This relationship followed a central-to-peripheral distribution, with macular tumors presenting earliest and anterior retinal tumors presenting last. Twenty-nine (100%) macular tumors were detected at the time of initial diagnosis, and none presented after 15.5 months of age. When controlled for surface area tumors were located equally in all circular zones. There is a time course in which tumors in different parts of the retina come to clinical presentation. All macular tumors in this study and the majority of tumors in the posterior pole were detected before age 24 months. The authors provide possible explanations for these findings and their implications for treatment.