Chronic Myeloid Leukemia with cryptic Philadelphia translocation and extramedullary B-lymphoid blast phase as an initial presentation

Acta Biomed. 2018 Apr 3;89(3-S):38-44. doi: 10.23750/abm.v89i3-S.7219.

Abstract

Chronic Myeloid Leukemia (CML) is a clonal myeloproliferative neoplasm (MPN) characterized by the presence of a reciprocal translocation between the long arms of chromosomes 9 and 22, t(9;22)(q34:q11), resulting in fusion of the break point cluster region (BCR) with the ABL gene, which forms an oncogene, the transcript of which is an oncoprotein with a tyrosine kinase function. In the great majority of CML; BCR/ABL1 is cytogenetically visualized as t(9;22); giving rise to the Ph chromosome, harboring the chimeric gene. Cryptic or masked translocations occur in 2-10% patients with no evidence for the BCR/ABL rearrangement by conventional cytogenetics but are positive by Fluorescence in Situ Hybridization (FISH) and/or reverse transcriptase polymerase chain reaction (RT-PCR). These patients are described as Philadelphia negative (Ph negative) BCR/ABL1- positive CML with the chimeric gene present on the derivative chromosome 22, as in most CML cases, or alternatively on the derivative 9 in rare occasions. In the majority of cases, CML is diagnosed in the chronic phase; it is less frequently diagnosed in accelerated crises, and occasionally, its initial presentation is as acute leukemia. The prevalence of extramedullary blast phase (BP) has been reported to be 7-17% in patients with BP. Surprisingly, no extra-medullary blast crises of B- lymphoid lineage have been reported before among cases of CML as the initial presentation. We report an adult male diagnosed as CML- chronic phase when he was shortly presented with treatment-naive extramedullary B-lymphoid blast crises involving multiple lymph nodes, with no features of acceleration or blast crises in the peripheral blood (PB) and bone marrow (BM). In addition the patient had variant/cryptic Philadelphia translocation. This is the first report of CML, on the best of our knowledge, with extramedullary B-lymphoid blast phase, as initial presentation, that showed a cryptic Ph translocation.

Publication types

  • Case Reports

MeSH terms

  • Antineoplastic Combined Chemotherapy Protocols / administration & dosage
  • Antineoplastic Combined Chemotherapy Protocols / therapeutic use
  • B-Lymphocytes / pathology*
  • Biomarkers, Tumor
  • Blast Crisis / genetics*
  • Blast Crisis / pathology
  • Cyclophosphamide / administration & dosage
  • Dasatinib / administration & dosage
  • Dexamethasone / administration & dosage
  • Doxorubicin / administration & dosage
  • Humans
  • In Situ Hybridization, Fluorescence
  • Leukemia, Myelogenous, Chronic, BCR-ABL Positive / diagnosis
  • Leukemia, Myelogenous, Chronic, BCR-ABL Positive / drug therapy
  • Leukemia, Myelogenous, Chronic, BCR-ABL Positive / genetics*
  • Leukemia, Myelogenous, Chronic, BCR-ABL Positive / pathology
  • Lymph Nodes / pathology
  • Male
  • Middle Aged
  • Philadelphia Chromosome*
  • Protein Kinase Inhibitors / administration & dosage
  • Vincristine / administration & dosage

Substances

  • Biomarkers, Tumor
  • Protein Kinase Inhibitors
  • Vincristine
  • Dexamethasone
  • Doxorubicin
  • Cyclophosphamide
  • Dasatinib

Supplementary concepts

  • CVAD protocol