Evidence of clonality in chronic neutrophilic leukaemia

Autoimmune hemolytic anemia complicating a chronic neutrophilic leukemia: A case report of a rare association

Key Clinical Message

Chronic neutrophilic leukemia is a rare disease with a poor prognosis. Its diagnosis is challenging in the lack of genetic tools. It can infrequently be associated with autoimmune hemolytic anemia.

Abstract

Chronic neutrophilic leukemia is a rare disease with poor prognosis, characterized by a sustained mature neutrophilic leukocytosis in the absence of monocytosis or basophilia with few or no circulating immature granulocytes, hepatosplenomegaly, and granulocytic hyperplasia of the bone marrow. In addition, no molecular markers for other myeloproliferative neoplasms are detected. The 2016 WHO classification included the presence of the CSF3R mutation as a key diagnostic criterion for this disease. Although anemia may be present at diagnosis, hemolytic one rarely complicates myeloproliferative neoplasms. Treatment is largely based on cytoreductive agents, but bone marrow allograft remains the only curative option. We report the case of a patient with chronic neutrophilic leukemia associated with autoimmune hemolytic anemia. We describe the epidemiological, clinical, prognostic, and therapeutic features of this disease in addition to the difficulties of its diagnosis and management in Tunisia.

Chronic myeloid leukemia: a type of MPN

This review article classifies chronic myeloid leukemia (CML) based on cytogenetic analyses and different mutations detected in CML patients. The use of advanced technologies, such as karyotyping, fluorescent in situ hybridization, and comparative genomic hybridization, has allowed us to study CML in detail and observe the different biochemical changes that occur in different CML types. This review also highlights the different types of receptor and signaling pathway mutations that occur in CML.

Analysis of gene mutation characteristics in patients with chronic neutrophilic leukaemia

Objective: This study aims to investigate the gene mutation characteristics of chronic neutrophilic leukaemia (CNL). Method: This study retrospectively analyses the molecular biological characteristics, laboratory characteristics and clinical data of four patients with CNL that were admitted in the second Hospital of Shanxi Medical University from May 2014 to October 2016. On the basis of the molecular biological data of 22 patients with CNL and 4 patients with CNL, we further analysed the characteristics of CNL molecular mutation. Results: Two out of the four patients with CNL were carriers of colony-stimulating factor 3 receptor (CSF3R) mutation, among which two were carriers of CSF3R T618I mutation combined with ASXL1 mutation and SETBP1 mutation, and two were only carriers of JAK2 V617F mutation. According to the molecular biological data of 22 patients with CNL, 20 patients were positive for CSF3R mutation. Two patients were positive for JAK2 V617F mutation. A total of 10 patients were positive for SETBP1 mutation which was correlated with the CSF3R T618I gene mutation (P = 0.03). A total of 13 patients were positive for ASXL1 mutation. No patients carried mutations in ASXL2 and MPL genes. Conclusion and Discussion: CSF3R mutation is the main tumorigenic mutation in CNL, in which CSF3R T618I mutation is the main mutation, and an extremely small number of CNL patients may be caused by JAK2 V617F mutation. SETBP1 and ASXL1 are the most common concomitant mutations in CNL with CSF3R mutation, and SETBP1 and CSF3R T618Imutations may have a certain correlation.

Leukemoid reaction: A 21st-century cohort study

INTRODUCTION

Leukemoid reaction (leukocyte count >50 cells ×10⁹  L) is a rare but extremely relevant finding. Since little has been published on this condition's clinical relevance and prognosis, we investigated leukemoid reaction in patients with a white blood cell count of >50 × 10⁹  L, including etiology and outcomes.

METHODS

This retrospective cohort study included all patients at a Brazilian tertiary hospital between January 2016 and July 2018 > 18 years with a total leukocyte count >50 cells×10⁹  L. Demographics, complete blood count, clinical features, and the exams used to diagnose and determine leukemoid reaction etiology were analyzed. A Kaplan-Meyer survival analysis was performed, and a binary logistic regression model identified variables associated with death.

RESULTS

Of the 267 cases with white blood cell count of >50 × 10⁹ , 162/267 (60%) were secondary to hematopoietic neoplasm and 105/267 (40%) presenting as a true leukemoid reaction. The primary causes of the true leukemoid reaction cases were infection (59), nonhematopoietic neoplasm (17), or other causes (29). Patient deaths (66) differed significantly between groups (P < .001, log-rank [Mantel-Cox] Test). Lower hemoglobin, older age, and increased segmented neutrophil count were associated with increased risk of death.

CONCLUSIONS

This was a modern cohort analysis of leukemoid reactions, inclusive of all etiologies. The most common cause was infection, which involved several microorganisms. Paraneoplastic leukemoid reaction was also common. Both conditions have a poor prognosis with high mortality, being a major medical challenge.

Chronic neutrophilic leukemia: new science and new diagnostic criteria

Chronic neutrophilic leukemia (CNL) is a distinct myeloproliferative neoplasm defined by persistent, predominantly mature neutrophil proliferation, marrow granulocyte hyperplasia, and frequent splenomegaly. The seminal discovery of oncogenic driver mutations in CSF3R in the majority of patients with CNL in 2013 generated a new scientific framework for this disease as it deepened our understanding of its molecular pathogenesis, provided a biomarker for diagnosis, and rationalized management using novel targeted therapies. Consequently, in 2016, the World Health Organization (WHO) revised the diagnostic criteria for CNL to reflect such changes in its genomic landscape, now including the presence of disease-defining activating CSF3R mutations as a key diagnostic component of CNL. In this communication, we provide a background on the history of CNL, its clinical and hemopathologic features, and its molecular anatomy, including relevant additional genetic lesions and their significance. We also outline the recently updated WHO diagnostic criteria for CNL. Further, the natural history of the disease is reviewed as well as potential prognostic variables. Finally, we summarize and discuss current treatment options as well as prospective novel therapeutic targets in hopes that they will yield meaningful improvements in patient management and outcomes.

[The clinical characteristics, gene mutations and prognosis of chronic neutrophilic leukemia]

Objective: To investigate the clinical manifestation, cytogenetics, gene mutations and prognostic factors of chronic neutrophilic leukemia (CNL) . Methods: 16 CNL cases, according to WHO (2016) -definition, were reviewed retrospectively. Identifications of the CSF3R, ASXL1, SETBP1, CALR and MPL mutations were performed by direct sequencing. JAK2 V617F mutation was detected by AS-PCR. Results: Of the 16 CNL patients, the median age was 64 (43-80) years with a male predominance of 75% (12/16) . The median hemoglobin was 114 (81-154) g/L, with median WBC of 41.20 (26.05-167.70) (10(9)/L and median PLT of 238 (91-394) ×10(9)/L.The median level of marrow fibrosis (MF) was 1 (0-3) degree. There was no other cytogenetic abnormalities except t (1;7) (p32;q11) , +21 and 14ps+ for each. All the 16 CNL patients harbored CSF3R T618I mutation. ASXL1 mutations were identified in 81% (13/16) , while SETBP1 mutations were confirmed in 63% (10/16) . The CALR K385fs*47 mutation was found. There was no mutation in JAK2 V617F or MPL in the above 16 patients. The median overall survival (OS) of patients presented with WBC≥50×10(9)/L at diagnosis (11 months) was significantly shorter than of WBC<50×10(9)/L (39 months, P=0.005) . Conclusion: CSF3R T618I mutation was specific for CNL. The median OS of CNL patients was 24 months, and WBC≥50×10(9)/L at diagnosis was an unfavorable prognostic factor.

[Chronic neutrophilic leukemia complicated with multiple myeloma: two cases report and literature review]

OBJECTIVE

To explored the diagnosis and treatment of chronic neutrophilic leukemia (CNL) complicated with multiple myeloma (MM).

METHODS

The clinical features and molecular biological characteristics of 2 patients with CNL complicated with MM were summarized, and the diagnosis and treatment of the patients were retrospectively reviewed.

RESULTS

The diagnosis of CNL complicated with MM was established in 2 cases. Case 1 had CSF3R mutation (P733T), but CSF3R-exon 14 mutation and SETBP1 mutation were all negative. The neutrophil count returned to normal when MM was successfully treated in case 1. When the patient relapsed, neutrophil count increased again.

CONCLUSION

Coexistence of CNL and MM is rare. CSF3R is a very important molecular marker for CNL. To the best of our knowledge, it's the first time to report the coexistence of CNL and MM carried CSF3R mutation (P733T). Chemotherapy regimens for MM may be effective in the treatment of CNL complicated with MM.

Chronic neutrophilic leukemia 2016: Update on diagnosis, molecular genetics, prognosis, and management

Chronic neutrophilic leukemia (CNL) is a potentially aggressive myeloproliferative neoplasm, for which current WHO diagnostic criteria include leukocytosis of ≥25 × 10(9) /L (of which >80% are neutrophils) and with <10 and <1% circulating immature granulocytes and blasts, respectively without dysplasia, clinical, or molecular criteria for other myeloproliferative disorders, nor an identifiable cause for physiologic neutrophilia in the absence of markers of myeloid clonality. Such a pathogenic clonal marker has now been identified as a somatic activating mutation of CSF3R, most commonly CSF3R T618I, thus demanding revision of the current WHO diagnostic classification to include the molecular criterion of mutated CSF3R. The clinical presentation, disease course and prognosis of CSF-R mutated CNL have been recently outlined. Co-operative mutations in SETBP1 and ASXL1 appear to be of prognostic significance and correlate with disease progression. Advances in the understanding of the molecular pathogenesis of CNL, have not yet fully translated into satisfactory therapeutic strategies, but the foundations for these are strengthening. Am. J. Hematol. 91:342-349, 2016. © 2015 Wiley Periodicals, Inc.

Chronic neutrophilic leukemia: a clinical perspective

Chronic neutrophilic leukemia (CNL) is a rare myeloproliferative neoplasm (MPN) that includes only 150 patients described to date meeting the latest World Health Organization (WHO) criteria and the recently reported CSF3R mutations. The diagnosis is based on morphological criteria of granulocytic cells and the exclusion of genetic drivers that are known to occur in others MPNs, such as BCR-ABL1, PDGFRA/B, or FGFR1 rearrangements. However, this scenario changed with the identification of oncogenic mutations in the CSF3R gene in approximately 83% of WHO-defined and no monoclonal gammopathy-associated CNL patients. CSF3R T618I is a highly specific molecular marker for CNL that is sensitive to inhibition in vitro and in vivo by currently approved protein kinase inhibitors. In addition to CSF3R mutations, other genetic alterations have been found, notably mutations in SETBP1, which may be used as prognostic markers to guide therapeutic decisions. These findings will help to understand the pathogenesis of CNL and greatly impact the clinical management of this disease. In this review, we discuss the new genetic alterations recently found in CNL and the clinical perspectives in its diagnosis and treatment. Fortunately, since the diagnosis of CNL is not based on exclusion anymore, the molecular characterization of the CSF3R gene must be included in the WHO criteria for CNL diagnosis.

Chronic neutrophilic leukemia with overexpression of EVI-1, and concurrent CSF3R and SETBP1 mutations: A case report

Chronic neutrophilic leukemia (CNL) is a rare type of myeloproliferative neoplasm, characterized by sustained neutrophilia, splenomegaly, bone marrow granulocytic hyperplasia (without evidence of dysplasia) and an absence of the Philadelphia chromosome. Thus far, ~150 cases of CNL have been described in the literature; however, none have demonstrated overexpression of the ecotropic viral integration site-1 (EVI-1, also known as MECOM) gene. The present study describes a case that fulfilled the World Health Organization diagnostic criteria for CNL, and was associated with overexpression of EVI-1, as well as novel concurrent mutations of colony stimulating factor 3 receptor (CSF3R) and SET binding protein-1 (SETBP1). In addition, the current study briefly reviewed the relevant literature regarding novel genetic findings associated with the diagnosis and treatment of CNL. To the best of our knowledge, this is the first case report of CNL with associated EVI-1 overexpression, and concurrent CSF3R and SETBP1 mutations.

Chronic neutrophilic leukaemia

Chronic neutrophilic leukaemia (CNL) is a rare type of myeloproliferative neoplasm (MPN) characterised by sustained leucocytosis (≥25×10(9)/L) with neoplastic proliferation of neutrophilic granulocytes in blood and bone marrow. In contrast to chronic myeloid leukaemia, the disease primarily involves neutrophilic lineage with persistent proliferation of mature forms of neutrophils. No consistent cytogenetic changes have been reported. Known recurrent genetic changes in other MPNs such as JAK2, MPL, CALR, BCR-ABL1, PDGFRA, PDGFRB and FGFR1 are mostly absent. Recently, mutations in colony stimulating factor 3 receptor (CSF3R) have been reported in high frequency in CNL. This discovery has provided more insight into its pathogenesis and opened up possible treatment options. In this article, we review the clinical findings, morphology, pathobiology and differential diagnosis of CNL and treatment implications of CSF3R mutations.

The molecular genetics of chronic neutrophilic leukaemia: defining a new era in diagnosis and therapy

PURPOSE OF REVIEW

In the current WHO classification of myeloid disorders, chronic neutrophilic leukaemia (CNL) is recognized as a myeloproliferative neoplasm characterized by sustained neutrophilic leukocytosis, hepatosplenomegaly and bone marrow granulocytic hyperplasia without evidence of dysplasia, BCR-ABL1 or rearrangements of PDGFRA, PDGFRB or FGFR1. This diagnosis is contingent upon exclusion of underlying causes of reactive neutrophilia particularly if evidence of myeloid clonality is lacking. The lack of a specific molecular marker has left the diagnosis to be largely one of exclusion. Recently, the molecular landscape shifted with the discovery of specific oncogenic mutations in the colony-stimulating factor 3 receptor gene (CSF3R) in CNL patients. We review the implications for diagnosis, pathogenesis and potential for new therapeutic options.

RECENT FINDINGS

In 2013, oncogenic mutations in CSF3R were identified in a majority of patients with CNL and demonstrated that their downstream signalling was sensitive to known kinase inhibitors. This discovery was then validated with the demonstration of 100% CSF3R mutational frequency (predominately CSF3RT618I) in strictly WHO-defined CNL. Simultaneously, novel somatic mutations in SETBP1 were found to be enriched in CNL with possible prognostic significance.

SUMMARY

CNL appears to be driven by specific somatic activating CSF3R mutations. These bestow susceptibility to known kinase inhibitors, opening the door to novel specific therapeutic options for CNL. The diagnosis of CNL will no longer be one only of exclusion, and revision of the current WHO diagnostic criteria is expected to include the molecular criterion of CSF3R mutation positivity.

Chronic neutrophilic leukemia 2014: Update on diagnosis, molecular genetics, and management

DISEASE OVERVIEW

Chronic neutrophilic leukemia (CNL) is a myeloproliferative neoplasm characterized by sustained, mature neutrophilic leukocytosis, splenomegaly, and bone marrow granulocytic hyperplasia.

DIAGNOSIS

Key diagnostic criteria include leukocytosis of >25 × 10(9) /l (of which >80% are neutrophils) with <10% and <1% circulating immature granulocytes and myeloblasts, respectively. There should be no dysplasia, monocytosis, molecular evidence of BCR-ABL1, PDGFRA, PDGFRB, or FGRF1 rearrangements and no identifiable cause for physiologic neutrophilia or, if present, demonstration of myeloid clonality. DEVELOPMENTS IN MOLECULAR GENETICS: Recently, CNL has been shown to be specifically driven by somatic activating mutations of CSF3R, most commonly CSF3R T618I. As such, the diagnosis of CNL will no longer be one of exclusion only, and revision of the current WHO classification is anticipated to include the molecular criterion of mutated CSF3R.

The new genetics of chronic neutrophilic leukemia and atypical CML: implications for diagnosis and treatment

Although activation of tyrosine kinase pathways is a shared theme among myeloproliferative neoplasms, the pathogenetic basis of chronic neutrophilic leukemia (CNL) has remained elusive. Recently, we identified high-frequency oncogenic mutations in the granulocyte-colony stimulating factor receptor (CSF3R) in CNL and in some patients with atypical chronic myeloid leukemia. Inhibition of Janus kinase 2 or SRC kinase signaling downstream of mutated CSF3R is feasible and should be explored therapeutically. Herein, we discuss the potential impact of these findings for the classification and treatment of these disorders.

Deletion of chromosome 17 as a novel cytogenetic finding in chronic neutrophilic leukemia: A case report

Chronic neutrophilic leukemia (CNL) is an infrequently encountered myeloproliferative disorder characterized by sustained neutrophilic leukocytosis, hepatosplenomegaly and the absence of the Philadelphia chromosome. This study presents a 60-year-old male patient with a diagnosis corresponding to the WHO classification criteria for CNL who was treated at the First Affiliated Hospital of Harbin Medical University (Harbin, China). Chromosome analysis of the patient’s bone marrow cells showed 44, XY, -17, -17 in all 20 metaphase spreads. Homoharringtonine was used to control the patient’s high white cell count for a short time, although after two weeks, the patient complained of left upper quadrant discomfort and his blood count showed a white blood cell count of 40.8×10⁹/l. However, the patient continued to undergo maintenance therapy and was discharged in good clinical condition with hydroxyurea treatment for 31 months. Usually, patients with CNL have normal karyotypes and no specific cytogenetic abnormalities have been identified. To the best of the authors’ knowledge, this is the first case in the literature of a patient exhibiting the deletion of chromosome 17 with CNL. We concluded that deleted of tumor suppressor genes located on 17p13.1, such as p53, may be associated with the development of CNL. Patients with CNL have a poor prognosis, although the present patient has exhibited a prolonged stable phase with oral chemotherapy drug treatment.

Partial reversal of the methylation pattern of the X-linked gene HUMARA during hematopoietic differentiation of human embryonic stem cells

Human embryonic stem cells (hESCs) can be induced to differentiate towards hematopoiesis with high efficiency. In this work, we analyzed the methylation status of the X-linked HUMARA (human androgen receptor) gene in hematopoietic cells derived from hESC line H9 before and after induction of hematopoietic differentiation. All passages of H9 and H9-derived hematopoietic cells displayed homogenous methylation pattern with disappearance of the same allele upon HpaII digestion. This pattern persisted in the great majority of different hematopoietic progenitors derived from H9, except in 11 of 86 individually plucked colonies in which an equal digestion of the HUMARA alleles has been found, suggesting that a methylation change occurring at this locus during differentiation. Interestingly, quantification of X inactive-specific transcript (XIST) RNA in undifferentiated H9 cell line and day 14 embryoid bodies (EB) by RT-PCR did not show any evidence of XIST expression either before or after differentiation. Thus, during self-renewal conditions and after induction of commitment towards the formation of EB, the methylation pattern of the HUMARA locus appears locked with the same unmethylated allele. However, hematopoietic differentiation seems to be permissive to the reversal of methylation status of HUMARA in some terminally differentiated progenitors. These data suggest that monitoring methylation of HUMARA gene during induced differentiation could be of use for studying hESC-derived hematopoiesis.

Monoclonal gammopathy of undetermined significance disguised as chronic neutrophilic leukemia

We encountered a 60-year-old woman with a medical history of diabetes mellitus, osteoporosis, peripheral vascular disease, and hypertension who had earlier presented at an outside facility with knee pain, which led to a finding of elevated neutrophil count of 35×10⁹/L. Because she was otherwise asymptomatic but continued showing elevated neutrophil levels, she sought a second opinion at our facility. Serum protein immunoelectrophoresis with immunofixation revealed an immunoglobulin A (IgA)-κ monoclonal gammopathy concentration of 1305 mg/dL (normal 80–350 mg/dL) but relatively normal concentrations of IgG of 840 mg/dL (620–1400 mg/dL) and IgM of 36 mg/dL (45–250 mg/dL). Using clonal analysis, we found a polyclonal expression pattern in all cell types analyzed. Comprehensive work-up for multiple myeloma and infectious etiology of neutrophilia was negative. We concluded that our patient’s neutrophilia may have been due to the underlying monoclonal gammopathy. This is the first case in the literature of a patient with monoclonal gammopathy of undetermined significance presenting with chronic neutrophilia, mimicking chronic neutrophilic leukemia (CNL). Patients with CNL have a poor prognosis; therefore, it is important to distinguish diagnostically between CNL and reactive neutrophilia.

Philadelphia chromosome-negative chronic myeloproliferative disease

Session 2 of the 2007 Workshop of the Society for Hematopathology/European Association for Haematopathology was focused on Philadelphia chromosome-negative chronic myeloproliferative diseases (Ph- MPDs), recently termed chronic myeloproliferative neoplasms. The presented and submitted cases highlighted some important issues and also impending problems associated with the diagnosis and classification. Cases included predominantly rare entities like chronic eosinophilic leukemia and related disorders, chronic neutrophilic leukemia, and others with specific genetic abnormalities that allowed molecularly targeted therapy. In this context, the distinctive role of a positive JAK2(V617F) mutation for the diagnosis of Ph- MPD was underscored, including entities with a low allele burden and the discrimination from reactive disorders (autoimmune myelofibrosis, reactive thrombocytosis). Although novel genetic and molecular approaches have significantly improved the way we classify Ph- MPD, a combined clinicopathologic approach, including representative bone marrow specimens, still remains the yardstick for diagnosis.

Chronic neutrophilic leukaemia: an Egyptian case

Chronic neutrophilic leukaemia (CNL) is a rare myeloproliferative disorder of elderly patients characterised by sustained neutrophilia. The diagnosis of CNL requires the exclusion of BCR/ABL positive chronic myelogenous leukaemia and leukemoid reaction. We present here a case of a 61-year-old Egyptian man with CNL and 21 months of follow-up. The main symptom of our patient was purpura. Splenomegaly, hepatomegaly and lymph node enlargement were not detected at presentation or throughout the patient's course. Thrombocytopenia was a considerable problem in our patient, causing recurrent bleeding and affecting the hydroxyurea dose adjustment. While hydroxyurea decreased the total leucocytic count, it could not affect the fatal course of the disease. The survival course of our patient extended to 21 months after presentation. The cause of death was attributed to disease progression.

Chronic neutrophilic leukemia with congenital Robertsonian translocation successfully treated with allogeneic bone marrow transplantation in a young man

We present a 23-year-old man with chronic neutrophilic leukemia (CNL). Physical examination revealed hepatosplenomegaly. Leukocytosis was evident with predominance of mature neutrophils with basophilic granules. Bone marrow aspiration revealed mature myeloid hyperplasia. Congenital Robertsonian translocation [45,XY,der(13;22)(q10;q10), in all of analyzed 20 cells] was detected; however, cytogenetic and molecular studies for 9:22 translocation were negative. He was diagnosed with CNL and hydroxyurea was started to control his symptoms and white blood cell count. He was then successfully treated with allogeneic bone marrow transplantation (BMT). Although the prognosis of CNL was not determined, curative therapy including allogeneic hematopoietic stem cell transplantation should be attempted in young patients with CNL.

Differential diagnostic challenge of chronic neutrophilic leukemia in a patient with prolonged leukocytosis

Our interesting case deals with the clinical and morphological aspects of a chronic neutrophilic leukemia and the critical evaluation of differential diagnosis of leukemoid reaction in bone marrow biopsies.

Renal abscess with Morganella morganii complicating leukemoid reaction

We report a case of leukemoid reaction (LR) complicating renal abscess caused by Morganella morganii infection in an 80-year-old man. On administration, laboratory tests revealed white blood cell count of 76160 /microL and C reactive protein 3.09 mg/dL. Although chronic myeloid leukemia was suspected, bcr/abl fusion transcript was not observed. Contrast enhanced computer tomography imaging of the abdomen showed abscess in the right kidney. M. morganii was detected repeatedly in material of liquid from the abscess and arterial blood culture. To our knowledge, this is the first case of M. morganii infection complicating LR.

The diagnosis of BCR/ABL-negative chronic myeloproliferative diseases (CMPD): a comprehensive approach based on morphology, cytogenetics, and molecular markers

Recent years showed significant progress in the molecular characterization of the chronic myeloproliferative disorders (CMPD) which are classified according to the WHO classification of 2001 as polycythemia vera (PV), chronic idiopathic myelofibrosis (CIMF), essential thrombocythemia (ET), CMPD/unclassifiable (CMPD-U), chronic neutrophilic leukemia, and chronic eosinophilic leukemia (CEL)/hypereosinophilic syndrome, all to be delineated from BCR/ABL-positive chronic myeloid leukemia (CML). After 2001, the detection of the high frequency of the JAK2V617F mutation in PV, CIMF, and ET, and of the FIP1L1–PDGFRA fusion gene in CEL further added important information in the diagnosis of CMPD. These findings also enhanced the importance of tyrosine kinase mutations in CMPD and paved the way to a more detailed classification and to an improved definition of prognosis using also novel minimal residual disease (MRD) markers. Simultaneously, the broadening of therapeutic strategies in the CMPD, e.g., due to reduced intensity conditioning in allogeneic hematopoietic stem cell transplantation and the introduction of tyrosine kinase inhibitors in CML, in CEL, and in other ABL and PDGRFB rearrangements, increased the demands to diagnostics. Therefore, today, a multimodal diagnostic approach combining cytomorphology, cytogenetics, and individual molecular methods is needed in BCR/ABL-negative CMPD. A stringent diagnostic algorithm for characterization, choice of treatment, and monitoring of MRD will be proposed in this review.

Classification and diagnosis of myeloproliferative neoplasms: the 2008 World Health Organization criteria and point-of-care diagnostic algorithms

The 2001 World Health Organization (WHO) treatise on the classification of hematopoietic tumors lists chronic myeloproliferative diseases (CMPDs) as a subdivision of myeloid neoplasms that includes the four classic myeloproliferative disorders (MPDs)-chronic myelogenous leukemia, polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF)-as well as chronic neutrophilic leukemia (CNL), chronic eosinophilic leukemia/hypereosinophilic syndrome (CEL/HES) and 'CMPD, unclassifiable'. In the upcoming 4th edition of the WHO document, due out in 2008, the term 'CMPDs' is replaced by 'myeloproliferative neoplasms (MPNs)', and the MPN category now includes mast cell disease (MCD), in addition to the other subcategories mentioned above. At the same time, however, myeloid neoplasms with molecularly characterized clonal eosinophilia, previously classified under CEL/HES, are now removed from the MPN section and assembled into a new category of their own. The WHO diagnostic criteria for both the classic BCR-ABL-negative MPDs (that is PV, ET and PMF) and CEL/HES have also been revised, in the 2008 edition, by incorporating new information on their molecular pathogenesis. The current review highlights these changes and also provides diagnostic algorithms that are tailored to routine clinical practice.

An update on the etiology and diagnostic evaluation of a leukemoid reaction

Persistent neutrophilic leukocytosis above 50,000 cells/muL when the cause is other than leukemia defines a leukemoid reaction. The diagnostic work-up consists of the exclusion of chronic myelogenous leukemia (CML) and chronic neutrophilic leukemia (CNL) and the detection of an underlying cause. The major causes of leukemoid reactions are severe infections, intoxications, malignancies, severe hemorrhage, or acute hemolysis. The present article points out the difficulties in the differential diagnosis of a leukemoid reaction and suggests an algorithm for a rational clinical and laboratory evaluation of this problematic entity.

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.

Classification of chronic myeloid disorders: From Dameshek towards a semi-molecular system

Hematological malignancies are phenotypically organized into lymphoid and myeloid disorders, although such a distinction might not be precise from the standpoint of lineage clonality. In turn, myeloid malignancies are broadly categorized into either acute myeloid leukemia (AML) or chronic myeloid disorder (CMD), depending on the presence or absence, respectively, of AML-defining cytomorphologic and cytogenetic features. The CMD are traditionally classified by their morphologic appearances into discrete clinicopathologic entities based primarily on subjective technologies. It has now become evident that most CMD represent clonal stem cell processes where the primary oncogenic event has been characterized in certain instances; Bcr/Abl in chronic myeloid leukemia, FIP1L1-PDGFRA or c-kit(D816V) in systemic mastocytosis, rearrangements of PDGFRB in chronic eosinophilic leukemia, and rearrangements of FGFR1 in stem cell leukemia/lymphoma syndrome. In addition, Bcr/Abl-negative classic myeloproliferative disorders are characterized by recurrent JAK2(V617F) mutations, whereas other mutations affecting the RAS signaling pathway molecules have been associated with juvenile myelomonocytic leukemia. Such progress is paving the way for a transition from a histologic to a semi-molecular classification system that preserves conventional terminology, while incorporating new information on molecular pathogenesis.

Atypical myeloproliferative disorders: diagnosis and management

Myeloid disorders constitute a subgroup of hematological malignancies that is separate from lymphoid disorders. The World Health Organization system for classification of tumors of the hematopoietic system divides myeloid disorders into acute myeloid leukemia and chronic myeloid disorders based on the presence or absence, respectively, of acute myeloid leukemia--defining morphological and cytogenetic features including the presence of 20% or more myeloblasts in either the bone marrow or the peripheral blood. A recently proposed semimolecular classification system for chronic myeloid disorders recognizes 3 broad categories: the myelodysplastic syndrome, classic myeloproliferative disorders (MPD), and atypical MPD. Classic MPD includes polycythemia vera, essential thrombocythemia, myelofibrosis with myeloid metaplasia, and chronic myeloid leukemia. Both myelodysplastic syndrome and BCR/ABL-negative classic MPD were previously discussed as part of the current ongoing symposium on hematological malignancies. The current review focuses on the diagnosis and treatment of both molecularly defined and clinicopathologically assigned categories of atypical MPD: chronic myelomonocytic leukemia, juvenile myelomonocytic leukemia, chronic neutrophilic leukemia, chronic basophilic leukemia, chronic eosinophilic leukemia, idiopathic eosinophilia including hypereosinophilic syndrome, systemic mastocytosis, unclassified MPD, and eosinophilic/mast cell disorders associated with mutations of platelet-derived growth factor receptors alpha (PDGFRA) and beta (PDGFRB), FGFR1, and KIT.

A case of transition of polycythemia vera to chronic neutrophilic leukemia

Chronic Neutrophilic Leukemia (CNL) is a rare myeloproliferative disorder characterized by a persistent increase of mature peripheral neutrophils, myeloid hyperplasia in bone marrow, hepatosplenomegaly, elevated neutrophil alkaline phosphatase (NAP) and absence of Philadelphia chromosome, with no evidence of infection or malignancy sufficient to mimic a leukemoid reaction. CNL has been associated with multiple myelomas in many reported cases, but transition of Polycythemia Vera (PV) to CNL is very rare. An 81-year-old female patient, who had undergone intermittent phlebotomy following the diagnosis of PV 8 years previously, was admitted to our hospital due to lower back pain. A physical examination showed a splenomegaly 2 cm below the costal margin, with tenderness of the thoracic and lumbar spine area. A peripheral blood examination showed a WBC count of 91,800/microL (neutrophil 88%) with a rare immature form, hemoglobin of 9.1 g/dL and a platelet count of 1,661,000/microL. Her NAP score was 58. The bone marrow examination showed 95% cellularity, with an M:E ratio of 10:1, increased megakaryocytes with normal morphology and the absence of myelofibrosis. Chromosomal studies showed no Philadelphia chromosome. A radiological examination showed compression fractures of the vertebrae and spinal cord compression. No underlying disease causing a leukemoid reaction was detected. With iron replacement, the hemoglobin level failed to increase over 12 g/dL. Therefore, it was concluded to be a transition of PV to CNL. After administration of hydroxyurea and vertebroplasty, the symptom improved and the WBC count was sustained below 40,000/microL.