| Stage | Description |
| 1 | localized tumor confined to area of origin; complete gross resection with or without microscopic residual disease; identifiable ipsilateral and contralateral lymph nodes negative macroscopically |
| 2A | localized tumor with incomplete gross excision; identifiable ipsilateral and contralateral lymph nodes negative microscopically |
| 2B | unilateral tumor with complete or incomplete gross resection with positive ipsilateral regional lymph nodes; contralateral lymph nodes negative microscopically |
| 3 | tumor infiltrating across the midline with or without regional lymph node involvement; unilateral tumor with contralateral regional lymph node involvement; midline tumor with bilateral lymph node involvement |
| 4 | dissemination of tumor to bone, bone marrow, liver, distant lymph nodes or other organs |
| 4s | limited to infants below 1 year of age. Localized primary tumor as defined for stage 1 or 2A or 2B with dissemination limited to liver, skin and/or bone marrow |