Chronic myelogenous leukemia and acute lymphoblastic leukemia occurring in the course of polycythemia vera

Acute Lymphoblastic Leukemia in the Course of Polycythemia Vera: A Case Report and Review of Literature

INTRODUCTION

Polycythemia vera (PV) is one of the most common forms of myeloproliferative neoplasms. Acute myeloid leukemia secondary to PV is well reported, and the mechanism has been clarified to some extent. Only a limited number of cases have been reported about the development of acute lymphoblastic leukemia (ALL) in the course of PV, and the possible underlying mechanism has not been explored well.

CASE PRESENTATION

A 75-year-old patient who developed ALL 3 years after he was diagnosed with PV. The presence of remarkable splenomegaly, typical immunophenotyping of the peripheral blood and increased expression of serum fibrosis markers indicated the existence of extramedullary hematopoiesis which may ascribe to myelofibrosis. After the treatment of dosage-modulated chemotherapy, the patient got complete remission.

CONCLUSION

The JAK2 mutation may the underlying factor that contributes to the development of ALL, and the existence of MF may indicate the progression to post- polycythemic MF, which may be a risk factor for the accelerated transformation.

Emergence of chronic myelogenous leukemia from a background of myeloproliferative disorder: JAK2V617F as a potential risk factor for BCR-ABL translocation

We report the emergence of chronic myelogenous leukemia (CML) in a patient with JAK2V617F-positive polycythemia vera after 15 years of phlebotomy. The polycythemia vera clinical and molecular findings were suppressed at the time of CML diagnosis, only to re-emerge after the leukemia was successfully treated with imatinib. We explored the potential association between myeloproliferative disorders and CML in the context of the current literature and found a higher-than-expected coincidence based on known epidemiologic data for each specific condition. We hypothesize that myeloproliferative disorder (JAK2V617F or molecular events that cause JAK2V617F) is a risk factor for CML (BCR-ABL translocation). Because of therapeutic implications, clinicians should be aware that the conditions co-occur more frequently than once thought.

Transformation of polycythemia vera to chronic myelogenous leukemia

Transformation of polycythemia vera to chronic myelogenous leukemia is a rare event. We report 2 women with long-standing polycythemia vera who developed chronic myelogenous leukemia. Both patients had no BCR/ABL1 fusion at the time of polycythemia vera diagnosis but were positive for the fusion at chronic myelogenous leukemia onset. Most patients with polycythemia vera have JAK2(V617F) mutation. Analysis of an archival bone marrow aspirate sample from 1 patient showed a heterozygous mutation status. The blood and bone marrow samples from the other patient showed the presence of homozygous JAK2(V617F) mutation and BCR/ABL1 fusion. The possible pathogenesis of such an event is discussed in the light of current literature.

Transition of polycythemia vera to chronic myeloid leukaemia

A 77-year-old female with polycythemia vera (PV) showed a sudden, typical chronic myeloid leukaemia (CML), 8 yr after the initial diagnosis, and an intermittent treatment with hydroxyurea (0.5-1 g/d) and phlebotomies. At PV diagnosis, the Ph chromosome was negative and no bcr-abl rearrangement was observed; they were both revealed positive at CML onset. Transition of PV to CML is very rare; only seven substantiated cases had been reported in the literature up until now (six from 1964 to 1993). All patients but one received (32)P or alkylating agents for PV treatment. The pathogenetic mechanisms are briefly discussed.

Non-treatment-related chronic myeloid leukemia as a second malignancy

The characteristics of the very rare non-treatment-related chronic myeloid leukemia (nTr-CML) cases have never before been analyzed. The literature up to December 2002 was screened using the Medline database to identify cases of Tr-CML and nTr-CML. We considered five cases with nTr-CML identified among 270 newly diagnosed CML at our Department. Our report thus considers nine cases with nTr-CML compared to 77 affected by Tr-CML as a secondary neoplasm. The median age at the appearance of the first tumor was higher in nTr-CML patients compared to that of the Tr-CML group (P<0.0001). The median age at CML diagnosis was significantly higher in the nTr-CML than in the Tr-CML group (P<0.0001). The proportion of hematological malignancies as first tumor type was not different in the two groups (44% in nTr-CML versus 56% in Tr-CML). Our study underlines that nTr-CML as a second malignancy is a rare entity associated with elderly age.

Classification and staging of Ph-negative myeloproliferative disorders by histopathology from bone marrow biopsies

The present study illustrates characteristic features of histopathology in the 3 non-leukemic, Ph-negative groups of chronic myeloproliferative diseases (CMPD). Attention is paid to the final outcome of CMPD, especially its transformation into acute leukemias and the occurrence of myelofibrosis from bone marrow biopsies (BMB) in a total of 1,716 CMPD patients. Essential thrombocythemia (ET), polycythemia vera (P. vera), and chronic megakaryocytic granulocytic myelosis (CMGM) can readily be distinguished by histopathology from BMB in the great majority of patients without regarding laboratory data, leaving a compartment of about 12% unclassifiable cases. Histologic patterns of staging are the increase in number and pleomorphism of megakaryocytes (MK), increase in number and density of reticulin fibers and collagen fibrosis, and excess of blasts. These 3 criteria are each graded from 0 to 3 in every biopsy. From these, a staging results by means of the histology of BMB in each of the Ph-negative CMPD. This staging provides a classification by defined criteria which permits comparative studies, the possibility of monitoring the individual patients by follow-up histology, and offers a baseline for reliable evaluation of results from therapy protocols.