Chronic myeloid leukaemia (CML) presenting in B-lymphoblastic crisis: a diagnostic challenge

We report the case of a 75-year-old female presented with lethargy, Hb 93 g/L, WBC 64 x 10⁹/L, platelet 110 x 10⁹/L. Blood film showed blasts, myelocytes, metamyelocytes, neutrophils. Quantitative PCR detected p210 BCR::ABL1 transcript in sorted CD19+ cells, and sorted CD19- cells. Bone marrow smear was packed with blasts. Flow cytometry and bone marrow histology revealed B-lymphoblasts. The patient was diagnosed with CML Blymphoblastic crisis. CML presenting in B-lymphoblastic crisis could resemble features of de novo Ph+ B-ALL, which makes the diagnosis challenging. These patients have inferior outcomes; therefore, it is important to distinguishing CML B -lymphoblastic crisis from de novo Ph+ B-ALL. Positive BCR::ABL1 in both CD19+ and CD19- sorted cell populations support the diagnosis of CML B-lymphoblastic crisis in this case.