Correlation between clinical features, magnetic resonance imaging, and histopathologic findings in retinoblastoma: a prospective study.

OBJECTIVE: To correlate clinical features with histopathology findings in advanced intraocular retinoblastoma and to determine the diagnostic accuracy of magnetic resonance imaging (MRI) in detecting tumor invasion.
DESIGN: Prospective, nonrandomized case series. PARTICIPANTS: We included 75 patients with group E retinoblastoma.
METHODS: Demographic and clinical features were recorded at presentation. Contrast-enhanced MRI was performed to study tumor characteristics and extent of invasion. Primary enucleation was performed and histopathologic features noted. Statistical analysis was done using the Kruskal-Wallis test to determine correlation between clinical features and histopathology. Sensitivity, specificity, and accuracy of MRI in detecting tumor invasion were determined. MAIN OUTCOME MEASURES: Significant associations between clinical findings at presentation and high-risk histopathology, and correlation between MRI results and histopathologic evidence of tumor invasion.
RESULTS: A significant association was found between iris neovascularization and choroidal invasion (P = 0.032), intraocular pressure and optic nerve invasion (P = 0.034), and shallow anterior chamber and iris invasion (P = 0.021). Corneal diameter did not show any significant correlation with high-risk histopathology. On MRI, tumor volume showed a significant association with optic nerve invasion (P = 0.023). The accuracy of MRI in detecting choroidal invasion was 68% (sensitivity, 60%; specificity, 80%). Prelaminar invasion was correctly identified in 9 out of 15 eyes (accuracy, 84%; sensitivity, 60%; specificity, 90%), whereas the accuracy of MRI in detecting postlaminar invasion was 76% (sensitivity, 61.9%; specificity, 81.5%). Ciliary body invasion was correctly identified in 5 out of 7 eyes (accuracy, 93.3%; specificity, 95.6%) and scleral invasion in 5 out of 6 eyes (accuracy, 98.7%; specificity, 100%).
CONCLUSIONS: As far as we are aware, this is the first prospective study on the correlation of clinical features and MRI findings with histopathologic risk factors in eyes primarily enucleated for retinoblastoma. Neovascularization of iris, intraocular pressure, shallow anterior chamber, and tumor volume correlated well with high-risk histopathology. Because MRI has limitations in reliably predicting microscopic infiltration of the choroid and optic nerve, decision in favor of neoadjuvant chemotherapy on the basis of suspected postlaminar invasion on MRI is not justified in the absence of histopathologic evidence of disease.