Abstract
T-acute lymphoblastic leukemia/lymphoblastic lymphoma (T-ALL/LBL) is rare and aggressive leukemia. Philadelphia chromosome positive (Ph+) is the most common cytogenetic abnormality in chronic myeloid leukemia (CML) and B-acute lymphoblastic leukemia (B-ALL). Ph+ T-ALL is exceeding rare and has a therapeutic and prognostic significance. The incidence and outcome of Ph+ T-ALL are unknown. Differentiation between Ph+ T-ALL/LBL and T-cell lymphoblastic crises of CML may be difficult. We report a rare case of adult de novo T-ALL with significant monocytosis, having Ph+ with (P190 BCR-ABL1) as a cytogenetic abnormality. He was treated with ALL induction chemotherapy and imatinib and achieved complete remission, then relapsed twice and expired shortly after the last CNS relapse.