Biphenotypic (mixed myeloid/T-cell) extramedullary myeloid cell tumor

A 32-year-old male with a 4-year history of chronic myelogenous leukemia (C ML) in chronic phase for 4 years, then myeloid blast crisis for 7 months, d eveloped diffuse bulky lymphadenopathy in association with a whits blued co unt (WBC) of 17,100/mm(3) with 70% blasts. Biopsy of a cervical lymph node revealed a blastic extramedullary myeloid cell tumor, which showed a biphen otypic (mixed myeloid/T-cell) immunophenotype. Chromosomal analysis reveale d karyotypic features of both myeloid and lymphoid lineages. Although extra medullary myeloid cell tumor (EMT, granulocytic sarcoma, chloroma) is well known to occur in chronic myelogenous leukemia (CML), to our knowledge this is the first description of evolution of CML into a biphenotypic EMT.