Basophilic leukemia in recurrent chronic myelogenous leukemia blast phase

Blast phase in chronic myelogenous leukemia is skewed toward unusual blast types in patients treated with tyrosine kinase inhibitors: a comparative study of 67 cases

OBJECTIVES

To compare the features of the blast phase of chronic myelogenous leukemia (CML) in patients treated with tyrosine kinase inhibitors (TKIs) with those in the pre-TKI era.

METHODS

Sixty-seven patients with blast phase CML were identified in the Duke Pathology database from 1991 to 2011. The morphology and immunophenotype of blasts were evaluated, along with cytogenetic studies and associated findings in the peripheral blood and bone marrow.

RESULTS

In the TKI era, the blasts were more frequently of a type other than the usual myeloid or lymphoid types when compared with the pre-TKI era. Blast phase in TKI-treated patients was associated with a higher peripheral WBC count and a lower blast percentage in the bone marrow. Of the 23 patients with cytogenetic studies during blast phase, additional cytogenetic changes more frequently occurred in patients with an unusual blast type, and some patients showed these changes months before the onset of blast phase.

CONCLUSIONS

Blast phase CML in TKI- and non-TKI-treated patients differs in the morphology and immunophenotype of blasts, cytogenetic findings, and associated findings in the peripheral blood and bone marrow.

Deletion of ABL/BCR on der(9) associated with severe basophilia

Chronic basophilic leukemia is a rare form in chronic myeloid leukemia patients. Only limited number of reports are available. Herein, we describe a patient who presented with fatigue, weight loss, leucocytosis, prominent basophilia, and mild eosinophilia. On biopsy, bone marrow was hypercellular with marked basophils. The immunophenotype showed abnormal expression of CD7, which is suggestive of basophilic maturation. Chromosomal analysis from GTG-banded metaphases revealed Ph positivity, and fluorescence in situ hybridization (FISH) with BCR/ABL dual color, dual fusion probe showed single fusion on the der(22) chromosome and ABL/BCR fusion was deleted on the der(9) chromosome. The deletion (ABL/BCR) on der(9) may be associated with basophilia which may be also indicative of the transformation of CML to acute myeloid leukemia.

Chronic basophilic leukemia: a rare form of chronic myeloproliferative neoplasm

Chronic basophilic leukemia is a rare and poorly characterized entity. Only a limited number of cases have been described. Herein, we report a patient who presented with fatigue, weight loss, leukocytosis, persistent prominent basophilia, and mild eosinophilia. The bone marrow showed features characteristic of a myeloproliferative neoplasm with a marked increase in maturing basophils. The basophils exhibited nuclear hypersegmentation, abnormal granulation, and abnormally low CD38 expression. Conventional karyotyping revealed a t(5;12)(q31;p13). ETV6 but not PDGFRB rearrangement was detected by fluorescence in situ hybridization.