由于化疗的进展,目前儿童急性淋巴细胞白血病(急淋)3年的无病存活者在50%以上。但是约有16～24%完全缓解3年或超过3年的患儿,在化疗停止后复发,多数在化疗停止后第1年复发。髓外白血病浸润对长期存活的急淋患儿说来是更为突出的临床问 Due to the progress of chemotherapy, the current childhood acute lymphoblastic leukemia (acute lymphoblastic) 3 years of disease-free survival in more than 50%. However, about 16 to 24% of children with complete remission for 3 years or more than 3 years have relapsed after the chemotherapy has stopped, most of which recur in the first year after the chemotherapy is stopped. Extramedullary leukemia infiltration of long-term survival of acute lymphoblastic children is more prominent clinical question