Primary Chronic Myelogenous Leukemia Blast Crisis with Precursor B Lymphoblastic Leukemia, a Case Report

Abstract

Abstract Introduction/Objective Primary chronic myelogenous leukemia (CML) blast crisis at the initial disease presentation is rare. Most CML blast crisis cases present with increased myeloblasts with a minority of patients showing lymphoblastic leukemia. Differentiating primary CML lymphoblast crisis from de novo acute lymphoblastic leukemia may represent a diagnostic challenge to both pathologists and treating clinicians. This distinction is important as it has significant implications on patient management. Methods/Case Report A 15-year-old male patient was admitted to our University Hospital for hyperleukocytosis. Patient reportedly had weight loss with occasional sweats and cervical lymphadenopathy. She was found to have massive splenomegaly. Peripheral blood showed hyperleukocytosis with predominance of granulocytes at all maturation stages ranging from blast to segmented neutrophils with increased blasts. Subsequent bone marrow findings were consistent with extensive involvement by B-lymphoblastic leukemia. Ten-color Flow cytometry showed approximately 30% blasts with rare lymphocytes and monocytes. The blasts revealed precursor B-lymphoblastic immunophenotypic expression of CD45, CD10, CD19, CD20, CD22, CD34, CD38, CD200, HLA-DR and TdT expression. The results were similar to that of peripheral blood. Granulocytes showed abnormal maturation pattern with increased immature precursors and partial expression of CD4 and CD56 with no abnormalities detected in lymphocytes. In this case, while the bone marrow findings are consistent with B-lymphoblastic leukemia, the peripheral blood findings are consistent with blast phase of chronic myeloid leukemia. Further evaluation by cytogenetic and molecular studies confirmed the presence of Philadelphia chromosome, p210 transcripts, and rearrangement of BCR-ABL1, which supported the impression of precursor B-lymphoblastic leukemia in primary blast phase of CML. The patient was treated with tyrosine kinase inhibitor combined chemotherapy and went into remission. She has been followed up without significant complications for a year. Results (if a Case Study enter NA) NA. Conclusion The diagnosis of CML in primary lymphoblastic crisis is rare and needs to be systemically excluded before giving the diagnosis of de novo BCR-ABL1-positive acute lymphoblastic leukemia. If the patient does not have splenomegaly or previous leukocytosis, it needs cytological examination and extensive molecular analyses.