MYELOPROLIFERATIVE DISORDERS Riadi Wirawan Departemen Patologi Klinik FKUI-RSCM

MYELOPROLIFERATIVE DISORDERS

Riadi Wirawan

Departemen Patologi Klinik FKUI-RSCM

Hoffbrand AV, Moss PAH, Pettit JE. Essential haematology .5th ed. Oxford : Blackwell Publishing; 2006.p.2.

Diagrammatic representation of the BM pluripotent stem cell and the cell line that arise from it.

MYELOPROLIFERATIVE DISORDERS (MPD)

JAK2 MUTATION

Polycythemia Vera (PV)

Essential thrombocythemia (ET)

Myelofibrosis (MF

BCR-ABL FUSION GENE

Chronic myeloid leukemia (CML)

MYELOPROLIFERATIVE DISORDERS (MPD)

MPD : a group of conditions characterized by clonal

proliferation of one or more hematopoietic

components in the BM and in many cases the liver

and spleen

Disorders are include :

Polycythemia vera (PV)

Essential thrombocythemia (ET)

Myelofibrosis


Relationship between the three myeloproliferative diseases. They may all arise by somatic mutation in the pluripotential stem and progenitor cells. Many transitional cases occur showing features of two conditions and, in other cases, the disease transforms during its course from one of these diseases to another or to acute myeloid leukaemia. The three diseases, polycythaemia rubra vera, essential thrombocythaemia and myelofibrosis, are characterised by JAK2 mutation in a varying proportion of cases.

This disorders are closely related to each other

Transitional form occur

A single acquired mutation of the cytoplasmic

tyrosine kinase Janus-associated kinase 2 (JAK-

2)(Val617Phe) occurs in the marrow and blood of

almost all patients with PV, 50% with ET and

myelofibrosis

The role of JAK2 mutation in the generation of myeloproliferative diseases. (a) (i) Most haemopoietic growth factor receptors do not have intrinsic kinase activity but associate with a protein kinase such as JAK2 in the cytoplasm. (ii) When the receptor binds a growth factor the cytoplasmic domains move closer together and the JAK2 molecules can activate each other by phosphorylation. (iii) The V617F JAK2 mutation allows the JAK protein to become activated even when no growth factor is bound.


The role of JAK2 mutation in the generation of myeloproliferative diseases. (c) JAK2 activation leads to cell survival and proliferation through activation of three major pathways; the STAT transcription factors, the PI3K pathway acting through Akt and Ras activation which subsequently activate ERK and MAPK. The net result is production of a diverse range of proteins that promote cell survival and proliferation.


Normal Primary or secondary

polycythaemia

Relative

polycythaemia

Total red cell volume

(51Cr)

♂ 25-35 mL/kg

♀ 22-32 mL/kg

N

Total plasma volume

(125I-albumin)

40-50 mL/kg N


Total red cell volume and total plasma volume

POLYCYTHEMIA

Is define as an increased in the Hb

concentration above the upper limit of normal

for the patient age and sex


Causes of polycythemia

Primary• Polycythemia (rubra) vera

• Familial (congenital) polycythemia

Secondary• Caused by compensatory erythropoietin increase in:

high altitudes pulmonary disease and alveolar hypoventilation (sleep apnoe) cardiovascular disease, especially congenital with cyanosis increased affinity haemoglobin (familial polycythemia heavy cigarette smoking

• Caused by inappropriate erythropoietin increased in:

renal diseases (e.g. hydronephrosis, vascular impairment, cysts, carcinoma) tumours such as uterine leiomyoma, hypernephroma, hepatocellular carcinoma, cerebellar haemangioblastomaRelative

• Stress or pseudopolycythemia

• Cigarette smoking

• Dehydration: water deprivation, vomiting

• Plasma loss: burns, enteropathy

POLYCYTHEMIA VERA

Polycythemia vera (PV)

Increased in red cell volume caused by a clonal malignancy of the marrow stem cell

The disease result from somatic mutation of a single hematopoietic stem cell (JAK-2 mutation is present in almost 100 % of patients)

Increased in red cells volume is the diagnostic finding and an overproduction of granulocyte and platelet

Chromosome abnormality : del 9p, del 20q

Clinical features

Common in older subjects, with an equal sex incidence Hyperviscosity :

Headache, dispnoe, blurr vision Phletoric appearance : ruddy cyanosis Bleeding : GI, uterine, cerebral Thrombosis : arterial (cardiac, cerebral, peripheral)

venous (leg veins, cerebral, portal, hepatic) Hypervolemia : retinal venous engorgement, hypertension Hypermetabolism

Night sweat Pruritus Gout Peptic ulcers

Splenomegali : 75% patients

Hoffbrand AV, Pettit JE. Color atlas of clinical hematology. 2nd ed. London : Mosby-Wolfe; 1998.p.198.

Gouty tophi on the index and middle fingers.

Laboratory findings

Increased hemoglobin concentration, hematocrit, RBC, total red cell volume (TRCV), blood viscosity and low serum erythropoietin

Leucocyte : Neutrophil leucocytosis Basophilia Increased Neutrophil Alkaline Phosphatase

(NAP) score Increased vit B12 and vit B12 binding capacity Increased uric acid serum and normal LDH

Thrombocyte count raise in about 50 % patients

Bone marrow

Hypercellular

Prominent megakaryocyte

Laboratory findings

Criteria for diagnosis of polycythemia (rubra) vera

A1 Total red cell mass male > 35 mL/kg female > 32 mL/kg

A2 Arterial oxygen saturation normal (> 92%)

A3 Splenomegaly

A4 JAK2 mutation

B1 Platelets > 400 x 109/L

B2 White cells > 12 x 109/L

B3 Increased NAP score (n : 10-100)

B4 Raised serum vitamin B12 levelA1 + A2 + A3 or A1 + A2 + A4 orA1 + A2 + another two BNAP = neutrophil alkaline phosphatase.


Treatment

Maintain a normal blood count, Ht should be maintain at 45 % and platelet count < 400.000/uL

Venesection : To reduce hematocrit < 45% Rapid reduction of red cell volume Resulting IDA, does not control the platelet count

Cytotoxic myelosuppression Poor tolerance of venesection, symptomatic, progressive

splenomegaly, weight loss, night sweat Hydroxyurea for controlling the blood count, side effects

myelosuppression, skin toxicity and nausea

Treatment

Phosphorus32 therapy

Use for older patients with severe disease

Late development of leukemic

Interferon alpha

Suppress excess proliferation in the marrow

Low dose aspirin : reduce thrombotic complication

Course and prognosis

Prognosis is good, median survival 10-16

years

Major clinical problems : thrombosis and

hemorrhage

Transformation PV to :

Myelofibrosis ( 30 %)

Acute leukemia (5 %)

ESSENTIAL THROMBOCYTHEMIA

Essential thrombocythemia

Megakaryocyte proliferation

Increased platelet count

Overproduction of platelet

Normal hematocrite

Philadelphia chromosome or BCR-ABL fusion gene

are absent

No collagen fibrosis in the marrow

Persisting platelet count > 400.000/uL,

exclude thrombocytosis by other causes

before diagnosis can be made

JAK-2 mutation in 50 % cases

Essential thrombocythemia


Causes of a raised platelet count

Reactive

• Haemorrhage, trauma, postoperative

• Chronic iron deficiency

• Malignancy

• Chronic infections

• Connective tissue disease (e.g. rheumatoid arthritis)

• Post-splenectomy

Endogenous

• Essential thrombocythaemia (JAK2 mutation + or -)

• In some cases of polycythaemia vera, myelofibrosis

and chronic myeloid leukaemia

Clinical features

Thrombosis : Venous Arterial

Hemorrhage : Result of abnormal platelet function May cause chronic or acute bleeding

Erythromelalgia : burning sensation felt in the hands or feet and reliaved by aspirin

Splenomegaly or splenic atrophy (infarction)

Hoffbrand AV, Pettit JE, Moss PAH. Essential haematology .4th ed. Oxford : Blackwell Science; 2001.p.230.

Gangrene of the left fourth toe in thrombocythaemia essential.

Laboratory findings

Peripheral blood Thrombocytosis with abnormal large platelet Megakaryocyte fragment may be seen in PB Abnormal platelet aggregation with

adrenaline

Bone marrow : excess of abnormal megakaryocyte

Cytogenetics : negative BCR-ABL fusion gene

Essential thrombocythaemia : peripheral blood film showing a gross increase in platelet numbers.

Treatment

To control platelet count so as to reduce the risk of thrombosis (risk > 60 years, thrombocyte > 1.000.000/uL, with previous episode of thrombosis or hemorrhage, smoking history and hypertension)

Keep the platelet count below 600.000/uL Hydroxyurea most widely use Alpha interferon valuable in younger patient Anagrelide for reducing the platelet count Plateletpheresis helpful in short term management Aspirin to reduce thrombotic risk

Course

Stationery 10 – 20 years Transform to myelofibrosis or acute leukemia

MYELOFIBROSIS

Myelofibrosis

Myelofibrosis is a clonal stem cell disease, in

some patient there is osteosclerosis

Progressive generalized reactive fibrosis of

the bone marrow in association with the

development of hemopoiesis in the spleen

and liver (myeloid metaplasia)

JAK mutation occurs in ± 50 % cases

No specific cytogenetic abnormalities

1/3 patients have a previous history of PV

Clinical feature

Insidious onset in older people as usual with

anemia

Massive splenomegaly

Hypermetabolic symptom : loss of weight,

anorexia, fever and night sweat

Bleeding problem, bone pain or gout

Laboratory findings

Anemia but normal or increase hemoglobin

level may be found

Leucocytosis and thrombocytosis are

frequent at the time of presentation, later

leucopenia and thrombocytopenia are

common

Leucoerythroblastic blood film : immature

granulocyte with NRBC

Tear drop cells

Bone marrow : unobtainable by aspiration,

trephine biopsy showed fibrotic hypercellular

marrow, increase megakaryocyte, increase

bone formation

Increased NAP score

High serum urate and LDH level increase

turn over cell

JAK-2 mutation in 50 % cases

Laboratory findings

Peripheral blood film in essential thrombocythaemia showing increased numbers of platelets and a nucleated megakaryocytic fragment.


Course

Transformation to acute myeloid leukemia (AML) 10 – 20 % cases

Median survival 3,5 years Cause of death : heart failure, infection and

leukemic transformation Poor prognosis if :

Hb < 10 g/dL WBC < 4000/uL Thrombocyte < 30.000/ul Presence of abnormal chromosome

CHRONIC MYELOID LEUKEMIA (CML)

Clonal disorders of a pluripotent stem cell

15% of leukemia & and may occur at any age

CML characteristic present of Philadelphia (Ph)

chromosome, t(9;22) (q34;q11) resulting

BCR-ABL fusion gene codes for a fusion

protein of size p210

CML

The Philadelphia chromosome. (a) There is translocation of part of the long arm of chromosome 22 to the long arm of chromosome 9 and reciprocal translocation of part of the long arms of chromosome 9 to chromosome 22 (the Philadelphia chromosome). This reciprocal translocation brings most of the ABL gene into the BCR region on chromosome 22 (and part of the BCR gene into juxtaposition with the remaining portion of ABL on chromosome 9). (b) The breakpoint in ABL is between exons 1 and 2. The breakpoint in BCR is at one of the two points in the major breakpoint cluster region (M-BCR) in CML or in some cases of Ph+ ALL. (c) This results in a 210-kDa fusion protein product derived from the BCR-ABL fusion gene. In other cases of Ph+ ALL, the breakpoint in BCR is at a minor breakpoint cluster region (m-BCR) resulting in a smaller BCR-ABL fusion gene and a 190-kDa protein.



(d) Karyotype showing the t(9;22) (q34;q11) translocation. The Ph chromosome is arrowed. (e) Visualization of the Philadelphia chromosome on: (i) dividing (metaphase); and (ii) quiscent (interphase) cells by fluorescence in situ hybridization (FISH) analysis (ABL probe in red and BCR probe in green) with fusion signals (red/green) on the Ph and der(9) chromosomes.

(e)

Occur in either sex (male : female ratio = 1,4 : 1)

Most frequency between age 40-60 yo

Hypermetabolism : weight loss, anorexia or night

sweats, gout

Splenomegaly

Anemia : pallor, dyspnoe & tachycardia

Leukostasis : visual disturbances and priapism

Abnormal platelet function : bruising, epistaxis,

menorrhagia or haemorhage

Clinical features

Hoffbrand AV, Pettit JE. Color atlas of clinical hematology. 2nd ed. London : Mosby-Wolfe; 1998.p.198.

CML: ocular fundus in the hyperviscosity syndrome shows distended retinal veins and deep retinal haemorrhages at the macular. Hb: 14 g/dL; WBC: 590 x 109/L; platelets: 1050 x 109/L

CML: acute inflammation and swelling of the fourth finger due to uric acid deposition. Hb: 8.6 g/dL; WBC: 540 x 109/L; platelets: 850 x 109/L; serum uric acid: 0.85 mmol/L.

Normochromic normocytic anemia

Leukocytosis 50.000 - > 500.000/uL with complete

spectrum of myeloid cell, dominate neutrophils and

myelocytes, basophilia

Thrombocyte : ↑/N/↓

Neutrophil alkaline phosphatase score low. Raised

in MPD and infection

Hyperuricemia

BM hypercellular with granulopoietic predominant

Ph chromosome (+)

Laboratory findings


Chronic myeloid leukaemia: peripheral blood showing a vast increase in buffy coat. The white cell count was 532 x 109/L.

Chronic myeloid leukaemia: peripheral blood film showing various stages of granulopoiesis including promyelocytes, myelocytes, metamyelocytes and band and segmented neutrophils.

CML chronic phase

CML accelerated phase

CML blastic phase : Acute myeloid leukemia (AML)

Acute lymphoid leukemia (ALL)

Bilineage acute leukemia

Biphenotype acute leukemia

Course

The diagnosis of CML-AP may be made when one or more of the following are present : Blast 10-19% of WBC in PB and or nucleated BM cells Basophilia ≥ 20% Persistent thrombocytopenia (< 100.000/uL) unrelated to

therapy or persistent thrombocytosis (> 1.000.000/uL) unresponsive to therapy

Increasing spleen size and increasing WBC count unresponsive to therapy

Cytogenetic evidence of clonal evolution

Chronic myelogenous leukaemia, accelerated phase

Blast phase may be diagnose if ≥ 1 more is present : Blast 20% of WBC in PB and or nucleated BM cells Extramedullary blasts proliferation Large foci or cluster of blast in BM biopsy

Chronic myelogenous leukaemia, blastic phase

Prognosis

Death occur from : blast phase or intercurrent hemorrhage or infection

Prognostic according : age spleen size platelet count PB and BM blast cell on presentation

Documents

MYELOPROLIFERATIVE DISORDERS Riadi Wirawan Departemen Patologi Klinik FKUI-RSCM