A Rare Case of Chronic Myelogenous Leukemia Presenting asT-Cell Lymphoblastic Crisis

Chronic Myelogenous Leukemia in blast crisis can manifest as either myeloid (more common) or lymphoid blast crisis. Mostlymphoblastic crises are of B-cell lineage. T-cell blast crisis is extremely rare, with only a few reported cases. We present a caseof a middle-aged man who was diagnosed with CML on peripheral blood and bone marrow biopsy. Because of a generalizedlymphadenopathy noted at the time of diagnosis, a lymph node biopsy was also performed, which revealed a T-celllymphoblastic leukemia/lymphoma, BCR/ABL1 positive, with clonal evolution. This is a very rare manifestation of CML in blastcrisis with no standard treatment and with poor outcomes despite chemotherapy or allogeneic stem cell transplant. Given itsrarity, it would be difficult to develop standard chemotherapy protocols. We believe the treatment for this condition should besimilar to any lymphoid blast crisis. The patient was treated with induction chemotherapy (hyper-CVAD regimen) plusdasatinib for 3 cycles followed by sibling-donor allogeneic stem cell transplant and is currently on maintenance dasatinib andhas minimal residual disease at this time.