白血病细胞侵犯中枢神经系统 ,早期常先累及蛛网膜的浅表部分 ,脑脊髓管间皮仍完整 ,因而脑脊液 (CSF)中常无白血病细胞 ,此时一般也无中枢神经系统白血病 (CNSL)的临床表现。据研究 ,在光学显微镜下每毫升CSF中能发现 1个白血病细胞 ,CSF就存在 10 5个白血病细胞 ,此时病情已 Leukemia cells invade the central nervous system, usually involving the superficial part of the arachnoid in the early stage, and the cerebrospinal canal is still intact. As a result, there is usually no leukemia cells in the cerebrospinal fluid (CSF), and at this time, there is no clinical practice of CNSL which performed. According to the study, under the light microscope, one leukemia cell can be found per ml of CSF, there are 105 leukemia cells in CSF,