Intraocular seeds in retinoblastoma: A review of classification, management, and outcomes

Intraocular seeds in retinoblastoma are formed from dispersion of the tumor into the adjacent liquid or semiliquid compartments. They are highly resistant to traditional treatment modalities and remain the most important cause of treatment failure. Intraocular seeds can be focal or diffuse in the vitreous, retrohyaloid, subretinal or aqueous compartments. Intravitreal and intracameral chemotherapy with melphalan and/or topotecan have allowed targeted drug delivery in desired concentration to achieve improved outcomes of seed regression and globe salvage. Group E disease, diffuse and recurrent seeds, as well as anterior chamber seeds continue to have suboptimal prognosis. We review the published literature on intraocular seeds, the evolution of their management, and the outcomes and complications of established treatment modalities.