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Table 1 Descriptions of original INSS tumor stages [6]

From: Assessment of the validity of image-defined risk factors (IDRFs) in abdominal neuroblastoma

Tumor stageDescription
1Localized tumor with complete gross excision, with or without microscopic residual disease; representative ipsilateral lymph nodes negative for tumor microscopically. Nodes attached to and removed with the primary tumor may be positive.
2ALocalized tumor with incomplete gross excision; representative ipsilateral non-adherent lymph nodes negative for tumor microscopically.
2BLocalized tumor with or without complete gross excision, with ipsilateral non-adherent lymph nodes positive for tumor; enlarged contralateral lymph nodes negative microscopically.
3Unresectable unilateral tumor infiltrating across the midline (beyond the opposite side of the vertebral column) with or without regional lymph node involvement or midline tumor with bilateral extension via infiltration (unresectable) or lymph node involvement.
4Any primary tumor with dissemination to distant lymph nodes, bone, bone marrow, liver, skin, and/or other organs (except as defined for stage 4S disease).
4SLocalized primary tumor (as defined for stage 1, 2A, or 2B disease) with dissemination limited to skin, liver, and/or bone marrow (limited to infants younger than 1 year, marrow involvement of less 10% of total nucleated cells, and MIBG scan findings negative in the marrow).