High-risk histomorphological features in retinoblastoma and their association with p53 expression: An Indian experience

Introduction: Histopathological features in retinoblastoma are considered high-risk factors (HRF) for tumor progression and metastasis, thus their presence becomes an indication for adjuvant chemotherapy. Present study was undertaken to evaluate the incidence of HRF in retinoblastoma and to correlate them with p53 expression. Materials and Methods: This was a retrospective study where 17 diagnosed cases of retinoblastoma were included. Cases were re-evaluated for various histomorphological parameters. Immuno-histochemical analysis was done with p53 antibody by Streptavidin biotin method. Results: The patients were in the age range of 1.5-50 years. Common histological features included necrosis (70.5%), calcification (64.7%), and retinal detachment (58.8%). Incidence of various morphological parameters was anterior chamber seeding (47.2%), ciliary body involvement (29.4%), iris involvement (29.4%), choroid involvement (58.8%), scleral invasion (29.4%), extrascleral invasion (11.8%), and optic nerve infiltration (23.5%). p53 expression was present in four cases out of 13 cases (30.7%) and showed a significant association with choroid invasion (P = 0.02). Discussion: The presence of HRF should alert the physician for a possible metastasis, and such patients should be kept on regular follow-up to detect an early recurrence. p53 expression, a known poor prognostic indicator, showed significant association with choroid invasion, however, no association was seen with other HRF. Conclusion: Histopathological HRF have significant therapeutic and prognostic implications. The incidence of HRF is higher in developing countries as patients present with a more advanced stage of disease. p53 expression is significantly associated with choroid invasion out of all HRF.