T-cell blast crisis in chronic myeloid leukemia

Involvement of T cells in chronic myeloid leukemia is a rare event. Twenty-one cases of T-cell lymphoid blast crisis of chronic myeloid leukemia reported in the literature are reviewed, and evidence for T-lineage involvement is evaluated. Patients present with a distinctive clinical phenotype. Most frequently they are young males with extensive extramedullary deposits of blast cells, rapidly progressive lymphadenopathy, organomegaly and pleural involvement. Clonal cytogenetic evolution is common and survival short. The identification of this phenotype may be of clinical and prognostic significance.