Table 3

International retinoblastoma classification

Stage 0: Patients treated conservatively (subject to presurgical ophthalmologic classifications)

Stage I: Eye enucleated, completely resected histologically

Stage II: Eye enucleated, microscopic residual tumor

Stage III: Regional extensiona
     a) Overt orbital disease
     b) Preauricular or cervical lymph node extension

Stage IV: Metastatic disease
     a) Hematogenous metastasis:
          1. single lesion
          2. multiple lesions
     b) CNS extension:
          1. Prechiasmatic lesion
          2. CNS mass
          3. Leptomeningeal disease

Aerts et al. Orphanet Journal of Rare Diseases 2006 1:31   doi:10.1186/1750-1172-1-31