Pathological findings in enucleated eyes after intravitreal melphalan injection

The aim of this study is to evaluate the pathological findings of the eye after intravitreal melphalan for viable vitreous seeding from retinoblastoma. All enucleated eyes receiving an intravitreal injection of melphalan (10-50 μg in 0.05 cc) were evaluated for histological changes. Of 25 treated cases, 8 eyes needed enucleation because of phthisis, parent request, or new tumor development. One of the cases was excluded from the study because of a history of intra-arterial chemotherapy with melphalan. There was no case of needle-site scleral involvement by retinoblastoma cells. In two eyes receiving 50 μg melphalan, no viable retinoblastoma cell was detectable in the eye. Severe gliosis, vascular occlusion, retinal necrosis, hemorrhage and neovascularization were seen. Histologically, intravitreal melphalan for recalcitrant or recurrent vitreous seeds from retinoblastoma appears to provide acceptable vitreous seed control. It seems that higher doses could be destructive causing ischemic necrosis in the retina, severe gliosis and secondary neovascular changes as well as having a destructive effect on retinoblastoma cells.