A myeloproliferative disorder may hide another one

Philadelphia Chromosome Positive Chronic Myelogenous Leukemia Blastic Crisis in a Patient with Unusual Primary Myelofibrosis Characteristics; A Case Report

INTRODUCTION

Myeloproliferative neoplasms (MPNs) are divided into BCR-ABL positive Chronic myeloid leukemia (CML) and BCR-ABL negative MPNs including Polycythemia vera (PV), Essential Thrombocythemia (ET) and Primary myelofibrosis (PMF). Evaluation of the Philadelphia chromosome in MPNs is a diagnostic requirement for classic CML.

CASE REPORT

In 2020, a 37-year-old woman with negative cytogenetic testing for Janus kinase2 (JAK2), Calreticulin (CALR), myeloproliferative leukemia virus oncogene (MPL), and positive for BCR-ABL1 mutation with reticular fibrosis in bone marrow was diagnosed as CML. Some years ago, the patient had been diagnosed with PMF with evidence of histiocytic necrotizing lymphadenitis or Kikuchi-Fujimoto disease (KFD). The BCR-ABL fusion gene was initially evaluated which was negative. Then, Cutaneous squamous cell carcinoma (cSCC) was confirmed by Dermatopathologist with palpable splenomegaly and high white blood cell (WBC) count with basophilia. Finally, BCR-ABL was detected positive by the fluorescence in situ hybridization (FISH) and quantitative real-time polymerase chain reaction (qRT-PCR). In fact, the co-occurrence of PMF with CML was identified.

CONCLUSION

This case study highlighted the importance of some cytogenetic methods in the detection and classification of MPNs. It is recommended that physicians pay more attention to it and be aware of the planning treatment.

Myeloproliferative neoplasms with concurrent BCR-ABL1 translocation and JAK2 V617F mutation: a multi-institutional study from the bone marrow pathology group

Myeloproliferative neoplasms arise from hematopoietic stem cells with somatically altered tyrosine kinase signaling. Classification of myeloproliferative neoplasms is based on hematologic, histopathologic and molecular characteristics including the presence of the BCR-ABL1 and JAK2 V617F. Although thought to be mutually exclusive, a number of cases with co-occurring BCR-ABL1 and JAK2 V617F have been identified. To characterize the clinicopathologic features of myeloproliferative neoplasms with concomitant BCR-ABL1 and JAK2 V617F, and define the frequency of co-occurrence, we conducted a retrospective multi-institutional study. Cases were identified using a search of electronic databases over a decade at six major institutions. Of 1570 patients who were tested for both BCR-ABL1 and JAK2 V617F, six were positive for both. An additional five patients were identified via clinical records providing a total of 11 cases for detailed evaluation. For each case, clinical variables, hematologic and genetic data, and bone marrow histomorphologic features were analyzed. The sequence of identification of the genetic abnormalities varied: five patients were initially diagnosed with a JAK2 V617F+ myeloproliferative neoplasm, one patient initially had BCR-ABL1+ chronic myeloid leukemia, while both alterations were identified simultaneously in five patients. Classification of the BCR-ABL1-negative myeloproliferative neoplasms varied, and in some cases, features only became apparent following tyrosine kinase inhibitor therapy. Seven of the 11 patients showed myelofibrosis, in some cases before identification of the second genetic alteration. Our data, reflecting the largest reported study comprehensively detailing clinicopathologic features and response to therapy, show that the co-occurrence of BCR-ABL1 and JAK2 V617F is rare, with an estimated frequency of 0.4%, and most often reflects two distinct ('composite') myeloproliferative neoplasms. Although uncommon, it is important to be aware of this potentially confounding genetic combination, lest these features be misinterpreted to reflect resistance to therapy or disease progression, considerations that could lead to inappropriate management.

A case of Philadelphia chromosome positive myeloproliferative neoplasm in a pregnant woman with unusual primary myelofibrosis features

Myeloproliferative neoplasms (MPNs) are traditionally separated into BCR-ABL-positive chronic myeloid leukemia (CML), and BCR-ABL-negative MPNs including primary myelofibrosis (PMF), essential thrombocythemia (ET), and so forth. One of the diagnostic requirements for PMF and ET is the absence of the Philadelphia chromosome, while its presence is almost universally indicative of CML. However, a diagnostic dilemma arises when Philadelphia chromosome-positive MPNs lack the majority of the typical features seen in CML. Some of these classic CML features include basophilIa, marked leukocytosis, neutrophils left-shift with myelocytes bulge, and "dwarf" megakaryocytes. Presented here is a case of a 32-year-old pregnant patient who did not have typical morphologic findings for CML, and yet the Philadelphia chromosome was positive. The patient demonstrated some pathologic features that are commonly presented in PMF that included bone marrow reticulin fibrosis, leukoerythroblastosis, splenomegaly, and increased serum lactate dehydrogenase.

Emergence of chronic myelogenous leukemia during treatment for essential thrombocythemia

A 72-year-old male patient was initially diagnosed with essential thrombocythemia (ET), a Philadelphia chromosome-negative (Ph1(-)) chronic myeloproliferative disorder (CMPD), and was treated with hydroxyurea (HU). After 9 years of diagnosis of ET, his peripheral leukocytes gradually increased, while his platelet count showed a decrease. Bone marrow analysis disclosed Ph-positive chronic myelogenous leukemia (CML) in the chronic phase. Administration of imatinib mesylate (IM), a Bcr-Abl tyrosine kinase inhibitor (TKI), induced complete hematologic response in a month, but was discontinued after 4 months because of Grade 3 pleural effusion (PE). The treatment was switched to nilotinib which successfully induced a complete cytogenetic response (CCyR) after 5 months of TKI therapy and resolved the PE. Despite CCyR, however, ET recurred. Since then, the patient has been treated for 8 months with a combination of nilotinib and HU which has successfully controlled both CML and ET. This report includes a review of the characteristics of 15 reported cases with co-occurrence of CML and Bcr-Abl-negative CMPDs, including ours. Although rare, care needs to be taken since, despite the often similar clinical features of the two diseases, they require completely different treatments.