Evolution to acute myeloblastic leukemia from chronic neutrophilic leukemia with dysplastic features in granulocytic lineage

Chronic neutrophilic leukaemia and plasma cell-related neutrophilic leukaemoid reactions

Many cases reported as 'chronic neutrophilic leukaemia' have had an associated plasma cell neoplasm. Recent evidence suggests that the great majority of such cases represent a neutrophilic leukaemoid reaction to the underlying multiple myeloma or monoclonal gammopathy of undetermined significance. We have analysed all accessible reported cases to clarify the likely diagnosis and to ascertain whether toxic granulation, Döhle bodies and an increased neutrophil alkaline phosphatase score were useful in making a distinction between chronic neutrophilic leukaemia and a neutrophilic leukaemoid reaction. We established that all these changes occur in both conditions. Toxic granulation and Döhle bodies are more consistently present in leukaemoid reactions but also occur quite frequently in chronic neutrophilic leukaemia. The neutrophil alkaline phosphatase score is increased in both conditions and is of no value in making a distinction.

Chronic neutrophilic leukemia and chronic myelomonocytic leukemia: WHO defined

The World Health Organization (WHO) classification of myeloid disorders has provided updated parameters for the consistent diagnosis of two previously less than optimally defined chronic myeloid disorders, CNL and CMML. The classification of these disorders, which had been controversial, is now better defined and provides more clinically and biologically relevant disease definitions to enable uniform diagnosis and a framework to evaluate natural history and therapeutic interventions. CNL is now recognized as a distinct entity among the chronic myeloproliferative disorders and CMML is included within the new category of 'myelodysplastic/myeloproliferative diseases' (MDS/MPD). Predominant neutrophilia defines CNL whereas CMML is defined by predominant and monocytosis. In each case these defining features must be distinguished from reactive causes for the same in the absence of clear evidence of myeloid clonality (CNL and CMML) or dysplasia (CMML). The exclusion of underlying bcr/abl-driven oncogenesis is an essential component in the diagnosis of these chronic leukemic processes. The optimal therapy for both CNL and CMML remains uncertain. Current management decisions are based on small studies or extrapolated from therapeutic strategies that are effective in similar chronic, clonal myeloid disorders. Given the potential for evolution to acute leukemia or progressive refractory leucocytosis or cytopenias, allogeneic stem cell transplantation might be appropriate for younger patients. Continued reporting and investigation of specific therapeutic strategies and responses must be encouraged.

Acquired gain of an X chromosome as the sole abnormality in the blast crisis of chronic neutrophilic leukemia

Chronic neutrophilic leukemia (CNL) is a rare myeloproliferative disorder characterized by sustained neutrophilic leukocytosis and absence of the Philadelphia chromosome. Most patients with CNL have normal karyotypes, and no specific cytogenetic abnormality has been identified. We report here a patient with CNL that evolved to myeloid blast crisis. A 73-year-old man was admitted to the hospital because of marked leukocytosis (leukocyte count 112.5 x 10(9)/L with 91% segmented neutrophils) and massive hepatosplenomegaly that was diagnosed as CNL with a normal karyotype. After treatment with hydroxyurea for 7 months, the disease progressed to a blast crisis. Bone marrow showed myeloid hyperplasia with 21% myeloblasts, 15% promyelocytes, and marked dysplastic changes of neutrophils. Blastic cells were positive for CD10, CD13, CD14, CD33, CD34, and HLA-DR. Chromosome analysis of the bone marrow cells showed 46,XY,+X in all 20 metaphase spreads. We reviewed 15 cases of CNL terminating in the blast crisis and confirmed that all cases transformed into myeloid crises and had poor prognoses. Furthermore, to our knowledge, this is the first case showing the acquired gain of an extra X chromosome as a sole abnormality in CNL. The gain of an extra X chromosome may play an important role in the progression from chronic phase to the blast crisis of CNL.