Objective: To analyze the histopathologic features of the eyes with intraocular retinoblastoma primarily treated by enucleation in a tertiary cancer center in Jordan.

Material and Method: A retrospective case series of 50 eyes for 49 patients who had pathologically confirmed retinoblastoma after enucleation as primary therapy. The main outcome measures included demographics, laterality, international classification of intraocular retinoblastoma, choroid invasion, optic nerve invasion, anterior chamber invasion, and tumor differentiation.

Results: The median age at enucleation was 30 months. Twenty-seven (55%) patients were males, and 19 (39%) patients had bilateral retinoblastoma. High risk pathological features were seen as massive choroid invasion in 9 (18%) eyes, post-laminar optic nerve invasion in 7 (14%) eyes, and anterior chamber, iris or ciliary body invasion in 7 (14%) eyes. Thirty-seven (74%) tumors were well/moderately differentiated, and 13 (26%) were poorly differentiated. Poorly differentiated tumors presented later (median 31 months) than well/ moderately differentiated tumors (26 months) and were associated with a higher incidence of high-risk pathological features. No single ICRB group C eye had high-risk pathological features, while 17% and 4% of group D eyes and 28% and 33% of group E eyes had massive choroid invasion and post-laminar optic nerve invasion, respectively. Eighteen (36%) patients received adjuvant chemotherapy for high risk pathological features, and at median follow up of 40 months, no single case had metastasis or was dead.

Conclusion: Our pathologic findings were similar to the developed world. They were supportive of the predictive power of the international classification of retinoblastoma staging system for the likelihood of high risk pathological features. Poorly differentiated tumors were associated with a higher incidence of high risk pathological features than well/moderately differentiated tumors.