The International Classification of Retinoblastoma4
| Group | Features |
|---|---|
| A | Tumor ≤3 mm |
| B | Tumor >3 mm or macular location (≤3 mm to foveola), juxtapapillary location (≤1.5 mm to disc), clear subretinal fluid (≤3 mm from margin) |
| C | Tumor with subretinal and/or vitreous seeds ≤3 mm from tumor |
| D | Tumor with subretinal and/or vitreous seeds >3 mm from tumor |
| E | Extensive retinoblastoma occupying >50% of globe or neovascular glaucoma; opaque media from hemorrhage in anterior chamber, vitreous, or subretinal space; invasion of postlaminar optic nerve, choroid (>2 mm), sclera, orbit, anterior chamber |