A child with retinoblastoma undergoes Reese-Ellsworth classification. Under the International Classification of Retinoblastoma (ICRB/ABC classification), Group E tumors are defined by which criterion that makes them distinct from Group D?

• A Tumor involving more than 50% of retinal volume or presence of neovascular glaucoma, opaque media, or anterior chamber seeding ✓
• B Presence of subretinal seeding beyond 3 mm from tumor margin
• C Any tumor with vitreous seeding regardless of tumor size
• D Foveal or optic disc involvement regardless of other features

Explanation

In the ICRB (ABC classification), Group E represents the most severe category, defined by tumors occupying >50% of globe volume, or presence of neovascular glaucoma, opaque media from hemorrhage, invasion of anterior segment, ciliary body, orbit, or phthisis bulbi. Group D differs in having diffuse vitreous or subretinal seeding but without these end-stage features. The distinction matters because Group E tumors generally require enucleation, while Group D may be considered for systemic chemotherapy.

Reference: Khurana Comprehensive Ophthalmology, 7th ed.

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Written and medically reviewed by the StethoPrep medical team.