Philadelphia-positive chronic-phase chronic myeloid leukaemia after long-term remission of Philadelphia-negative acute lymphoblastic leukaemia.

摘要

A 54-year-old man presented to the haematology outpatient clinic with tiredness, occasional night sweats, axillary lymphadenopathy and a mild neutropenia. The peripheral blood showed a haemoglobin level of 11.5 g/dl, a white blood cell count of 4.6 X 10~9/l (with neutrophils 1.6 X 10~9/l) and a platelet count of 175 X 10~9/l. On the blood film examination there was a significant number of blasts. Bone marrow aspirate revealed a blast population of 24% of total marrow cells, but more significantly in the trephine biopsy, where the vast majority of the marrow space was occupied by a lymphoid blast population. The blasts were negative for myeloperoxidase, and on flow cytometry, the cells were positive for CD10 (48%), CD19 (36%), CD34 (9%), HLA-DR (92%) and moderately positive for TdT, in keeping with a diagnosis of common acute lymphoblastic leukaemia (ALL). Cytogenetic results revealed a normal male karyotype and no evidence of translocation (9;22) on 34 cells examined from unstimulated cultures. In situhybridization with BCR-ABL1 probes (Oncor) revealed no evidence in interphase cells of the BCR-ABL1 fusion at the molecular level when compared with a positive control. Southern blotting was negative for BCR-ABL1 rearrangement. Therefore, the patient was treated accordingto the chemotherapy arm of the UKALL XII protocol (2 induction phases followed by consolidation chemotherapy and maintenance treatment lasting 18 months incorporating vincristine, methotrexate, prednisolone, daunorubicin, asparaginase, cyclophosphamide, cytarabine, 6-mercaptopurine, etoposide, thioguanine and dexamethasone, cranial irradiation as 24 cGy in 21 fractions and intrathecal injections). He entered complete remission after the induction phase, and stem cells were harvested. Molecular analysis of the harvest was negative for the BCR-ABL1 rearrangement. He successfully proceeded through the consolidation and maintenance phase with sustained complete remission in his bone marrow, confirmed by flow cytometry.