Biphenotypic extramedullary blast crisis as a presenting manifestation of Philadelphia chromosome-positive CML in a child.

A 14-year-old child presented with generalized lymphadenopathy and massive hepatosplenomegaly. Peripheral smear and bone marrow examination were suggestive of Ph' positive chronic myeloid leukemia (CML) in chronic phase. However, lymph node biopsy showed extramedullary blast crisis with evidence of myeloid and T cell markers in blasts. Reverse transcriptase-polymerase chain reaction from lymph node aspirate revealed transcript for bcr-abl p210. Thus, we present here a unique case of childhood CML with extramedullary biphenotypic blast crisis (myeloid/T cell type) at initial presentation with bone marrow remaining in chronic phase. This case provides further evidence to the highly heterogeneous presentation of CML.