Progression to acute leukemia is an inherited feature of myelodysplastic syndrome (MDS). While majority of acute leukemia cases in this setting is acute myeloid leukemia (AML), rare cases of acute B-lymphoblastic leukemia/lymphoma (B-ALL) also exist. Therefore, detection of increased blasts in a patient with MDS should not be equated with a diagnosis of AML; full immunophenotyping of blasts is required. Previous reports indicate that dysplastic myeloid cells and B-lymphoblasts belong to the same clone. However, dysplastic myeloid cells and B-lymphoblasts could be clonally unrelated. Decitabine in addition to hyperCVAD (fractionated cyclophosphamide, vincristine, doxorubicin and dexamethasone alternating with high-dose methotrexate and cytarabine) could be a good treatment option in this particular clinical setting.