international neuroblastoma pathology classification: favorable histology group, patient age 1.5 years up to but less than 5 years, with differentiating neuroblastoma (schwannian stroma-poor), and low 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