Extramedullary T-lymphoblastic blast crisis in a young male with chronic myeloid leukemia: A rare presentation diagnosed on cytology and flow cytometric immunophenotyping.

Background: Extramedullary blast proliferations (EBPs) are known to occur in around 15% of chronic myeloid leukemia (CML) patients in the blast phase. Immunophenotypically, the EBPs are commonly myeloid as compared to the lymphoid. Amongst the lymphoid EBPs, T-lymphoblastic type is considerably rare.