Histopathologic changes in retinoblastoma after chemoreduction

Purpose: To report the histologic findings in the eyes of two patients with bilateral retinoblastoma who underwent chemoreduction therapy and enucleation of one eye. Methods: Clinical histories were obtained for both patients. The enucleated eyes were routinely processed and sections were stained with hematoxylin and eosin. Results: The first patient underwent two cycles of carboplatin, vincristine, and etoposide, and the second patient underwent one cycle of carboplatin, Vincristine, and etoposide before enucleation. The eyes of both patients exhibited a clinical type 3 regression pattern. Histopathologic examination showed a gliotic mass with interspersed calcifications in one eye and necrotic tumor adjacent to histotogically intact retinoblastoma in the other eye. Conclusion: Chemoreduction has Variable effects on retinoblastoma and the clinical type 3 regression pattern has several histologic counterparts.