Bi-lineage B- and T-lymphoid Extramedullary Blast Crisis at an Initial Presentation of Chronic Myeloid Leukemia: A Case Report and Literature Review of Extramedullary Blast Crisis

Chronic myeloid leukemia (CML) with BCR-ABL1-positive cells is a myeloproliferative neoplasm (MPN) characterized by a chromosomal translocation t(9,22)(q34.1;q11.2), which results in the formation of a Philadelphia (Ph) chromosome containing the BCR-ABL1 fusion gene. Extramedullary blast crisis (EBC) associated with bcr/abl-positive CML is a rare initial presentation. Here, we present and discuss the case of a 51-year-old man who presented with a weight loss history, cervical swelling, and left-sided abdominal pain. He had a white blood cell count of 147,910/mm3. The blood smear study revealed myelemia in 23% and 8% of blast-like cells. The bone marrow aspiration and biopsy showed a richly cellularized sample; the megakaryocytes were present; the granular neutrophil line was at 89% with blasts at 1%. The cytogenetic analysis revealed a complex karyotype with the presence of a Philadelphia chromosome t (9, 22) (q34, q11) associated with additional cytogenetic abnormalities (ACA). Molecular analysis (PCR) detected a BCR::ABL1 (p210) rearrangement. At this point, a diagnosis of CML in the chronic phase was confirmed, but a cervical lymph node biopsy analysis revealed a bi-phenotypic B/T-lymphoblastic lymphoma (LBL) and expressed at fluorescent in situ hybridization (FISH) analysis BCR::ABL1 rearrangement. These findings were consistent with the diagnosis of a bi-phenotypic B/T extramedullary blast crisis associated with CML.