Abstract

Chronic myeloid leukaemia is a tri phasic disease characterized by the presence of Philadelphia chromosome and/or molecular evidence of BCR/ABL hybrid gene in the hematopoietic cells. Natural course of disease has a chronic phase followed by an accelerated phase and finally leukemic phase or blast crisis. Extra medullary manifestation is rare and the sites commonly involved are skin, soft tissue, lymph node, GIT. However CNS as a site of extra medullary blast crisis is rare. Imatinib meyslate is a potent and selective inhibitor of BCR-ABL tyrosine kinase. However there is poor penetration of CNS by the drug and its metabolites. Therefore the CNS acts as a sanctuary site for malignant cells for CML. We report four cases of CML who relapsed with CNS involvement after passing from chronic to blastic/lukemic phase.

Keywords: Chronic myeloid leukemia; Central nervous system; Cerebral spinal fluid; Blast crisis; Chromosome; Tyrosine; Apoptosis