Case discussion & journal presentation

Dr. Maruf Reza Kabir

Phase-B resident

Dept. of Haematology

A-54y-old male with incidental high WBC & low platelet count

Particulars-

• Name- Mosharraf Hossain
• Age- 54y
• Sex- male
• Religion- Islam
• Occupation- service holder
• Address- Chadpur

Presentation-

• Incidental findings of high WBC & low platelet count
• Generalized weakness for 6 months

• No H/O-
• fever
• cough
• burning micturition
• joint pain
• bleeding
• wt loss

• Past history-
• Known diabetic for 9 years
• HTN for 2 years
• H/O 1 unit apheretic platelet transfusion within 7 days
• Drug history- antidiabetic, antihypertensive

​

General examination-

• Appearence- normal
• Body built- average
• Anaemia- mild
• Jaundice- absent
• Bony tenderness- absent
• Oedema- absent
• Lymphadenopathy- absent

• Temperature- 98.4 F
• RR- 14/m
• Pulse- 82/m
• BP- 130/70
• Wt- 62kg

Systemic examinations-

• Spleen i enlarged-
• 4 cm from lt costal margin towards rt iliac fossa
• non tender
• firm,
• splenic notch pesent
• No other organomegaly
• Other systemic examination reveals no abnormality

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Salient feature-

• Mr. Mosharraf Hossain 54 years of age diabetic, hypertensive hailing from Chadpur presentedted with the complaits of incidental haematological findings of high WBC & low platelet count. On quiry he complaints of weakness for 6 months though not hampering his daily activities
• He had no H/O fever, cough, burning micturition, loose stool, joint pain, wt loss.
• H/O just 1 unit apheretic platelet transfusion 1 week back

• O/E- he is mildly anaemic, no bony tenderness, no LN
• Systemic exam-
• moderate splenomegaly (18cm)
• no other orgnomegaly.
• other systemic examinations reveal no abnormality

Diagnosis??

• USG whole abdomen-
• Moderate splenomegaly (16 cm)
• Nephrolithiasis (lt)
• Enlarged prostate
• Chest Xray P/A view-
• Normal findings

BMS- 08/07/21

• Cellularity: Hypercellular
• M:E ratio: Increased (10:1)
• Erythropoiesis: Active, mainly normoblastic
• Granulopoiesis: Active, Maturation upto segmented form, plenty of myelocytes. Blasts are not increased
• Lymphocytes: normal
• Plasma cell: Occasionally seen.

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• Comment: Features are suggestive of myeloid hyperplasia, probably MPD. advised to exclude CML

Bone marrow/trephine- 28/07/21

• Aspirated marrow blood shows all three haematopoitic lineage cells. Granulopoisis is shift to the left having all spectrum of granulocytic series with features of dysgranulopoiesis with prdominance of neutrophil & myelocytes. Promyelocytes, blast & basophils are also increased. Monocytes are normal in number. Erythropoiesis is active & dyserythropiesis is seen. Megakaryocytes are decreased with few number of dysmegakaryopoiesis.

​

• Comment: Myelodysplastic/Myeloproliferative neoplasm

Trephine biopsy- 28/07/21

• Marrow celllarity is reduced. Myeloid to erythroid ration is increased. Erythropoiesis is reduced. Granulopoiesis is active including segmented form. Blasts are slightly increased in number with fibroproliferation. Megakaryocytes are seen but in hypolobulated form. Areas of fibrosis is also seen.

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• Comment : CML progressing to myelofibrosis

• Flowcytometry- 28/07/21
• Cell population positive for CD33, CD13, CD64, cMPO, CD 38, Negative for cyCD3, sm CD3, CD7, CD5, CD4, CD8, CD34, HLA DR, CD19, CD79, CD20

• BCR-ABL (peripheral blood) (RT PCR)

-P210, P190, P230- not detected

• JAK2 exon 12-15

-Negative

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• What is the diagnosis?
• What further investigations need to be done to conclude a dignosis?

• Chronic neutrophilic leukemia (CNL) is a rare BCR-ABL1 negative myeloproliferative neoplasm (MPN) characterized by sustained, predominantly mature neutrophil proliferation, bone marrow granulocytic hyperplasia and hepatosplenomegaly
• Rare neoplasm
• Median age at diagnosis of 66.5 years (range: 15-86)
• Slight male preponderance

Clinical features-

• Incidental neutrophilic leukocytosis in asymptomatic subject
• Antecedent chronic leukocytosis lasting a median of 12.5 months
• Constitutional symptoms- fatigue, pain, pruritus, easy bruising, gout
• Splenomegaly (36%) and/or hepatomegaly. lymphadenopathy uncommon.
• Bleeding diathes- cerebral hemorrhage (thrombocytopenia, platelet dysfunction, vascular wall infiltration by neoplastic cells)

• The hallmark of CNL is sustained, chronic, mature neutrophilia.
• CNL is distinguished by more mature granulopoietic forms compared with CML

• The hallmark of CNL is sustained, chronic, mature neutrophilia
• CBC-
• Preponderance of granulocytes (≥80%), segmented or band stage, minimal to no circulating blasts.
• Absence of monocytosis, basophilia or eosinophilia
• Mild anemia (median hemoglobin 11 g/dL)
• Thrombocytopenia
• Worsening thrombocytopenia along with increasing splenomegaly often herald disease progression or blast crisis.

Others-

• Eleveted LDH
• Raised LAP score
• Eleveted Vitamin B12 levels
• Low serum granulocyte-colony stimulating factor (G-CSF) levels
• Mutation-
• T618I vs other CSF3R mutations

• Bone marrow morphology-
• Hypercellular (>90%)
• Increased myeloid erythroid ratio (may be excess of 20:1)
• Majority of granulocyte precursors are present- metamyelocyte to segmented stages. ,5% Myeloblasts, absence of Auer rods. No dysplastic features. Reticulin staining may show minimal fibrosis
• Erythroid maturation is normoblastic
• Megakaryocytes morphologically normal, normal or slightly increased in number.

• Neutrophil morphology and function-
• Neutrophil toxic granulations and Dohle bodies (also observed in neutrophilic leukemoid reactions commonly)- may suggest an activated neutrophil state

WHO 2016 revised diagnostic criteria for CNL

• Peripheral blood leukocytosis ≥25 × 10^9/L
• Segmented neutrophils plus band forms ≥80% of WBC
• Neutrophil precursors (promyelocytes, myelocytes, metamyelocytes) <10% of WBC
• Myeloblasts rarely observed
• Monocyte count <1 × 10^9/L
• No dysgranulopoies
• Hypercellular Bone Marrow
• Neutrophil granulocytes increased in percentage and number
• Normal neutrophil maturation
• Myeloblasts <5% of nucleated cells

• Not meeting WHO criteria for BCR-ABL1+ CML, PV, ET or PMF
• No rearrangement of PDGFRA, PDGFRB or FGFR1 or PCM1-JAK2
• Presence of CSF3RT618I or other activating CSF3R mutation

or

• In the absence of a CSFR3R mutation- persistent neutrophilia (at least 3 months), splenomegaly and no identifiable cause of reactive neutrophilia including absence of a plasma cell neoplasm or if present, demonstration of clonality of myeloid cells by cytogenetic or molecular studies

Differential diagnosis-

• Reactive neutrophilia/ Leukemoid reaction
• CML
• CML-N
• Atypical CML
• CMML

Leukamoid reaction-

• CNL & leukemoid reaction- both may present with significant neutrophilia, BM hypercellularity, normal cytogenetics and absence of BCR-ABL1 fusion gene.
• The WBC count may be more modestly elevated in leukemoid reaction
• History & clinical examination- to exclude occult malignancy or infection
• Demonstration of clonality (CSF3R mutation or other) supports the diagnosis of CNL

• CML-
• BCR-ABL1 fusion gene
• Higher proportion of myelocytes
• More frequent basophilia, thrombocytosis and/or eosinophilia
• CML-N-
• Overlaps with the features of CNL, specifically prominent neutrophilia
• Uncommon
• BCR-ABL translocation, which results in 230-kD BCR-ABL protein
• Lower total WBC counts, less severe anemia, less frequent/severe splenomegaly and delayed blastic transformation

WHO 2016 revised diagnostic criteria for atypical CML

• Peripheral blood leukocytosis due to increased numbers of neutrophils and their precursors (promyelocytes, myelocytes and metamyelocytes) comprising ≥10% of leukocytes
• Hypercellular bone marrow with granulocytic proliferation and granulocytic dysplasia, with or without dysplasia in the erythroid and megakaryocytic lineages
• Dysgranulopoiesis, which may include abnormal chromatin clumping
• No or minimal absolute basophilia: basophils usually <2% of leukocytes
• Myeloblasts <20% in blood and bone marrow
• Not meeting WHO criteria for BCR-ABL1+ CML, PV, ET, or PMF
• No rearrangement of PDGFRA, PDGFRB, or FGFR1, or PCM1-JAK2

CMML-

• MPN/MDS overlap
• Persistent (≥3 months) peripheral monocytosis >1 × 109/L
• Absence of BCR-ABL1 fusion or PDGFRA/B rearrangements
• Presence of fewer than 20% blasts or promonocytes in blood and bone marrow
• Evidence of dysplasia or clonal abnormality

or

• persistent monocytosis lasting ≥3 months with exclusion of all other causes
• The chronic monocytosis and presence of dysplasia in CMML are central in distinguishing it from CNL

• A diagnosis of CNL also requires exclusion of other myeloid malignancies including polycythemia vera (PV), essential, thrombocythemia (ET), and primary myelofibrosis (PMF)
• Rarely, paraneoplastic leukocytosis may result from ectopic production of G-CSF by solid tumors (urological, lung, mesothelium) mimicking the neutrophilic leukocytosis of CNL
• Disease association- PV, plasma cell disorders

Molecular pathogenesis-

• CSF3R mutation (also in severe congenital neutropenia, hereditary chronic neutrophilia, myeloid leukaemia)
• Two variants-
• T618I (most common)
• T615A
• Additional mutation-
• ASXL1 (30-81%)
• SETBP1
• TET2 (14-56%)
• JAK2
• CALR
• EZH2
• KDM6A

​

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Karyotype- aberration-

• Monosomy 5 & 7
• Triosomy 21
• Deletion of 12p
• Monosomy 21

Prognosis & natural history-

• Fatal complications- intracranial hg
• Progressive disease-
• due to resitant to treatment
• progrssive refractory neutrophilia
• increasing transfusion dependency
• worsenig organomegaly
• aqusition of additional molecular & cytogenetic abnormalities
• Transformation to AML
• Blast crisis

Prognostics markers-

• Risk stratification-
• platelets <160 × 109/L (2 adverse points)
• leukocytes >60 × 109/L (1 point)
• presence of an ASXL1 mutation (1 point)
• Patients were allocated to low-risk (0-1 points) or high-risk (2-4 points)
• High-risk individuals undergo closer monitoring and possibly earlier HSCT

• ASXL1 mutations and thrombocytopenia- negatively impact survival
• SETBP1 mutations may promote disease transformation or refractoriness to treatment
• CSF3RT618I mutated individuals exhibited reduced life expectancy compared to other “variant” CSF3R-mutation
• NRAS, ASXL1, GATA2, and DNMT3A mutations were associated with shorter OS
• CBL mutations predicted more favorable survival

Management-

• Conventional therapy, oral chemtherpy, IFN
• JAK inhibitors
• Induction chemotherapy
• HSCT
• Novel agents

Conclusion-

• CNL is a rare, often clinically aggressive myeloid malignancy
• It is mostly a disease of exclusion
• Discovery of oncogenic CSF3R driver mutations in the majority of CNL patients provided the
• molecular backbone to a disease
• Concurrent mutations in ASXL1 are frequent and prognostically detrimental
• There are few effective treatment options
• The upcoming challenge will be enriching and operationalizing this data, integrating it along with cytogenetic and clinical variables and ultimately translating this into impactful therapeutic progress.