Sudden Dispersion of Retinoblastoma Shortly after Initial Chemotherapy Treatment

PurposeTo present 3 cases of unilateral retinoblastoma that demonstrated unusual tumor dispersion shortly after initial chemotherapy treatment.DesignObservational case series.MethodsReview of medical records of patients in whom intraocular dissemination of retinoblastoma occurred after initial treatment with chemotherapy.ResultsThree patients demonstrated an atypical response with intraocular dissemination of retinoblastoma shortly after 1 cycle of chemotherapy. All cases had unilateral retinoblastoma with no vitreous seeding or subretinal fluid at presentation. In 2 cases (Cases 2 and 3), there were a few distant subretinal seeds. Per the International Classification of Retinoblastoma, 1 tumor was group E (Case 1), and the other 2 tumors were group D1 (Cases 2 and 3). In 2 cases (Cases 1 and 2), chemotherapy included a 2-drug regimen of carboplatin and etoposide; in the third case, a 3-drug regimen of carboplatin, etoposide, and vincristine was used. In each case, the retinoblastoma dispersed with tumor cells in the vitreous shortly after initial chemotherapy treatment, leading to subsequent enucleation of the eye.ConclusionsRetinoblastoma can exhibit an unexpected and sudden dispersion of the tumor shortly after chemotherapy is initiated.