Successful Haploidentical Stem Cell Transplant With Posttransplant Cyclophosphamide for Isolated Central Nervous System Blast Crisis in a Child With Chronic Myeloid Leukemia.

Chronic myelogenous leukemia (CML) is a myeloproliferative disorder. The extramedullary blast crisis (BC) is a known complication of CML, but it usually accompanies a systemic disease. However, an isolated central nervous system (CNS) BC at relapse is very rare and has a very poor prognosis. Salvage is even more difficult for patients who relapse with a CNS BC after an allogeneic stem cell transplant (SCT). Here, we report successful treatment of an isolated CNS BC of CML in a 14-year-old boy who relapsed with isolated a CNS BC after matched sibling donor SCT by haploidentical SCT with posttransplant cyclophosphamide.