Cavitary changes in retinoblastoma: relationship to chemoresistance

To describe the clinical features and outcome of treatment of retinoblastomas presenting with ophthalmoscopically visible cavities.

Retrospective, noncomparative, interventional case series.

Sixteen eyes of 15 patients harboring retinoblastomas with ophthalmoscopically visible cavities treated between February 1995 and July 2003.

Patient demographics, eye and tumor characteristics, and response to treatment were recorded.

Decrease in tumor size and tumor recurrence.

The mean patient age at diagnosis was 20 months. The mean number of retinoblastomas per eye was 2 (range, 1-6). Associated subretinal fluid was graded as absent in 5 eyes, minimal in 6 eyes, mild in 4 eyes, and severe in 1 eye. None of the tumors had vitreous seeds, and 5 (31%) had subretinal seeds. Ophthalmoscopically visible calcification occupied a mean of only 3% of the tumor (median, 0%; range, 0%-30%). Intratumoral cavities were characteristically visible in the superficial portion of the tumor and had a mean diameter of 2.0 mm (median, 1.5; range, 0.5-5.0). The mean number of cavities per tumor was 2 (median, 1; range, 1-5). Three tumors were treated with enucleation, 1 with observation, and 12 with chemoreduction. Two months after chemoreduction, the mean reduction in tumor base was 19% (median, 16%; range, 0%-42%), and the mean reduction in tumor thickness was 18% (median, 12%; range, 0%-59%). During a mean follow-up of 32 months (median, 23; range, 12-58), none of the cavitary retinoblastomas recurred or gave rise to vitreous or new subretinal seeds.

Retinoblastomas containing ophthalmoscopically visible cavitary spaces do not show a substantial decrease in size after chemotherapy. Cavitary changes in retinoblastoma may be a sign that the tumor is well differentiated and may impart a better prognosis.