international neuroblastoma pathology classification: favorable histology group, patient less than 1.5 years of age, with poorly differentiated neuroblastoma (schwannian stroma-poor), and low or intermediate mitosis-karyorrhexis index
international neuroblastoma pathology classification: unfavorable histology group, patient 1.5 yr up to but less than 5 yr, with poorly differentiated neuroblastoma and any mki or differentiating neuroblastoma and intermediate or high mki