International neuroblastoma pathology classification: Unfavourable histology group, patient less than 1.5 years old, with poorly differentiated or differentiating neuroblastoma (Schwannian stroma-poor) and high mitosis-karyorrhexis index

International neuroblastoma pathology classification: Unfavorable histology group, patient less than 1.5 years old, with poorly differentiated or differentiating neuroblastoma (Schwannian stroma-poor) and high mitosis-karyorrhexis index (finding)