Presentation of chronic myeloid leukemia in basophilic blast crisis

Basophilia with mature and dysplastic basophils is a common phenomenon in CML. However, a basophilic blast crisis is a very rare form of acute transformation. A review of 410 patients with disease in transformation revealed only two cases (0.5%) of basophilic blast crisis.1 The dominance of basophil blast cells with fewer or no other myeloblasts or lymphoblasts confirms the diagnosis. Clonal evolution is likely to be evident with additional chromosomal abnormalities, often including i(17q) or other abnormality of chromosome 17.1-4 Diagnosis is straightforward when a patient is known to have CML but is more problematic if a patient presents already in blast crisis. The authors declare no conflict of interest.