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: 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