Clinical pathologic study of a cohort of patients with retinoblastoma from a developing country.

Purpose: To describe the histopathologic characteristics of all retinoblastoma biopsy specimens received at one institution.

Methods: All retinoblastoma biopsy specimens received between January 2000 and December 2005 were evaluated and a total of 109 eyes from 101 patients were studied.

Results: There were 9 (8.3%) well differentiated, 25 (23.0%) moderately differentiated, and 66 (60.5%) poorly differentiated retinoblastomas. The most common growth pattern was mixed, comprising 81 (74.4%) cases. Vitreous seeding, invasion of the anterior chamber, and invasion of the optic nerve beyond the lamina cribrosa, was present in 79 (72.5%), 24 (22.0%), and 44 (40.4%) eyes, respectively. The tumor was confined to the retina in only 26 (23.9%) cases, whereas 16 (14.8%) had minimal choroidal invasion, 45 (41.3%) had massive choroidal involvement, 10 (9.2%) had scleral invasion, and 11 (10.1%) had extraocular extension.

Conclusion: In this study, the percentage of patients with choroidal and optic nerve invasion, reflecting a poor prognosis, was much higher than in previously reported North American series. However, similar findings have been described in other developing countries, where late diagnosis is common. This study emphasized the need for early diagnosis and treatment.