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Myeloproliferative diseaseClassification and external resources

ICD-10 D47.1

ICD-9 205.1, 238.4, 289.89, 289.9

ICD-O: 9950/0-9964/3

MeSH D009196

REFERENCE » WIKIPEDIA ARTICLES

Myeloproliferative diseaseview original wikipedia article

The myeloproliferative diseases ("MPD"s)are a group of diseases of the bonemarrow in which excess cells areproduced. They are related to, and mayevolve into, myelodysplastic syndrome andacute myeloid leukemia, although themyeloproliferative diseases on the wholehave a much better prognosis than these conditions. The concept of myeloproliferative

disease was first proposed in 1951 by the eminent hematologist William Dameshek.[1]

In the most recent World Health Organization classification of Hematologicmalignancies, this group of diseases was renamed from "myeloproliferative diseases" to"myeloproliferative neoplasms". This reflects the underlying clonal genetic changes thatare a salient feature of this group of disease.

ClassificationAlthough not a malignant neoplasm like other cancers, MPDs are classified within thehematological neoplasms.

There are four main myeloproliferative diseases, which can be further categorized by thepresence of the Philadelphia chromosome:

Philadelphia Chromosome "positive" Philadelphia Chromosome "negative"

Chronic myelogenous leukemia (CML) Polycythemia vera (PV)Essential thrombocytosis (ET)Myelofibrosis (MF)

In 2001, the World Health Organization classified "chronic eosinophilic leukemia /hypereosinophilic syndrome" and chronic neutrophilic leukemia under "Chronic

myeloproliferative diseases".[2]

CausesAll MPDs arise from precursors of the "myeloid" lineage in the bone marrow. Thelymphoid lineage may produce similar diseases, the lymphoproliferative disorders (acutelymphoblastic leukemia, lymphomas, chronic lymphocytic leukemia and multiplemyeloma).

DiagnosisDepending on the nature of the myeloproliferative disorder, diagnostic tests may includered cell mass determination (for polycythemia), bone marrow aspirate and trephinebiopsy, arterial oxygen saturation and carboxyhaemoglobin level, neutrophil alkaline

phosphatase level, vitamin B12 (or B12 binding capacity) and serum urate.[3]

According to the WHO Classification of Hematopoietic and Lymphoid Neoplasms 2008myeloproliferative disorders are divided into the following by diagnostic characteristics:

1. Chronic myelogenous leukemia (CML) with defining translocation t(9;22) BCR-ABLtranslocation which has three breakpoints:

2. Primary myelofibrosis associated with JAK2 mutation in up to 50% of cases and MPL(thrombopoietin receptor) mutation in up to 5% of cases

a. u-BCR-ABL (p230): leads to CML with usual neutrophilia and basophilia. b. minor-BCR-ABL (p190): leads to CML which has a tendency to become acute lymphoblastic leukemia (ALL) usually precursor B ALL and rarely precursor T ALL. c. major-BCR-ABL (p210): normal usual breakpoint

a. Cellular phase - increased megakaryocytes which cluster, reticulin fibrosis, later trichrome (collagenous) fibrosis, and increased myeloid

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3. Polycythemia vera associated most often with JAK2 mutation in up to 80% of cases

4. Essential Thrombocythemia associated with JAK2 mutation in up to 20% of casesand MPL (thrombopoietin receptor) mutation in up to 15% of cases

These disorders are still being revised according to more specific genetic mutations andhow often patients end in a fibrotic marrow event.

In 2005, the discovery of the JAK2 V617F mutation provided some evidence to suggest

a common pathogenesis for the Philadelphia Chromosome negative MPDs.[4][5][6][7][8]

References1. ↑ Dameshek W (1951). "[Expression error: Missing operand for > Some speculations on the

myeloproliferative syndromes]". Blood 6 (4): 372–5. PMID 14820991.

2. ↑ "Classification of Human Hematopoietic Malignancies".http://emice.nci.nih.gov/emice/mouse_models/organ_models/hema_models/hema_human_class.

3. ↑ Levene, Malcolm I.; Lewis, S. M.; Bain, Barbara J.; Imelda Bates (2001). Dacie & Lewis PracticalHaematology. London: W B Saunders. p. 586. ISBN 0-443-06377-X.

4. ↑ Baxter EJ, Scott LM, Campbell PJ, et al. (2005). "[Expression error: Missing operand for > Acquiredmutation of the tyrosine kinase JAK2 in human myeloproliferative disorders]". Lancet 365 (9464): 1054–1061. doi:10.1016/S0140-6736(05)71142-9. PMID 15781101.

5. ↑ James C, Ugo V, Le Couedic JP, et al. (2005). "[Expression error: Missing operand for > A uniqueclonal JAK2 mutation leading to constitutive signalling causes polycythaemia vera]". Nature 434 (7037):1144–1148. doi:10.1038/nature03546. PMID 15793561.

6. ↑ Levine RL, Wadleigh M, Cools J, et al. (2005). "[Expression error: Missing operand for > Activatingmutation in the tyrosine kinase JAK2 in polycythemia vera, essential thrombocythemia, and myeloidmetaplasia with myelofibrosis]". Cancer Cell 7 (4): 387–397. doi:10.1016/j.ccr.2005.03.023. PMID15837627.

7. ↑ Kralovics R, Passamonti F, Buser AS, et al. (2005). "[Expression error: Missing operand for > A gain-of-function mutation of JAK2 in myeloproliferative disorders]". N Engl J Med 352 (17): 1779–1790.doi:10.1056/NEJMoa051113. PMID 15858187.

8. ↑ Campbell PJ, Scott LM, Buck G, et al. (2005). "[Expression error: Missing operand for > Definition ofsubtypes of essential thrombocythaemia and relation to polycythaemia vera based on JAK2 V617Fmutation status: a prospective study]". Lancet 366 (9501): 1945–1953. doi:10.1016/S0140-6736(05)67785-9. PMID 16325696.

External linksMyeloproliferative Disorders Website of The CMPD Education FoundationMyeloproliferative Disorders in practiceMyeloproliferative Disease Support List Free daily digest, 2850 subscribers 40+countriesMeSH Myeloproliferative+DisordersMyeloproliferative Disorders Research ConsortiumMPD Foundation - Free newsletter and patient brochure

This disease article is a stub. You can help Wikipedia by expanding it.

Myeloid Hematological malignancy/leukemia histology (ICD-O 9590-9989, C81-C96,200-208)

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precursors b. Fibrotic phase - collagenous fibrosis with lack of marrow elements

a. Cellular phase - increased megakaryocytes which cluster, reticulin fibrosis, later trichrome fibrosis, and increased myeloid and erythroid precursors b. Fibrotic phase - collagenous fibrosis with lack of marrow elements

a. Cellular phase - increased large megakaryocytes with fibrosis and little increase in other bone marrow elements b. Fibrotic phase - collagenous fibrosis with lack of marrow elements

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Myeloproliferative disorders are a group of slow-growing blood cancers, including chronic myelogenousleukemia, in which large numbers of abnormal red blood cells, white blood cells, or platelets grow andspread in the bone marrow and the peripheral blood.

The following PDQ treatment summaries are available:

Childhood Acute Myeloid Leukemia/Other Myeloid MalignanciesIncludes childhood myelodysplastic syndromes and other myeloproliferative disorders. [ patients ] [ health professionals ] Acute Myeloid Leukemia [ patients ] [ health professionals ] Chronic Myelogenous Leukemia [ patients ] [ health professionals ] Chronic Myeloproliferative Disorders [ patients ] [ health professionals ]

Subsections of this summary include:Polycythemia VeraChronic Idiopathic MyelofibrosisEssential ThrombocythemiaChronic Neutrophilic LeukemiaChronic Eosinophilic Leukemia

Myelodysplastic SyndromesIncludes refractory anemia, refractory anemia with excess blasts, refractory anemia with ringedsideroblasts, refractory cytopenia with multilineage dysplasia, unclassifiable myelodysplastic syndrome,and myelodysplastic syndrome associated with del (5q). [ patients ] [ health professionals ]

Subsections of this summary include:

De novo Myelodysplastic SyndromeSecondary Myelodysplastic SyndromePreviously Treated Myelodysplastic Syndrome

Myelodysplastic/Myeloproliferative Diseases [ patients ] [ health professionals ]

Subsections of this summary include:

Chronic Myelomonocytic LeukemiaJuvenile Myelomonocytic LeukemiaAtypical Chronic Myeloid LeukemiaMyelodysplastic/Myeloproliferative Disease, Unclassifiable

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ICD10 = D75.2, D47.3Classification and external resources

ICD-9 238.71

ICD-O: M9962/3

OMIM 187950

DiseasesDB 4522

MedlinePlus 000543

eMedicine med/2266

MeSH D013920

REFERENCE » WIKIPEDIA ARTICLES

Essential thrombocytosisview original wikipedia article

'Essential thrombocytosis (ET, also knownas essential thrombocythemia) is a rarechronic blood disorder characterized bythe overproduction of platelets bymegakaryocytes in the bone marrow inthe absence of an alternative cause. Insome cases this disorder may beprogressive, and rarely may evolve intoacute myeloid leukemia ormyelofibrosis. It is one of fourmyeloproliferative disorders.

EpidemiologyEssential thrombocytosis is diagnosed at a rate of about 2 to 3 per 100,000 individuals

annually.[1][2] The disease usually affects middle aged to elderly individuals, with anaverage age at diagnosis of 50–60 years, although it can affect children and young

adults as well.[3]

PathophysiologyThe pathologic basis for this disease is unknown. However, essential thrombocytosisresembles polycythemia vera in that cells of the megakaryocytic series are moresensitive to growth factors. Platelets derived from the abnormal megakaryocytes do notfunction properly, which contributes to the clinical features of bleeding and thrombosis.

In 2005, a mutation in the JAK2 kinase (V617F) was found by multiple research groups[4][5][6] to be associated with essential thrombocytosis in around 30% of cases. JAK2 isa member of the Janus kinase family. This mutation may be helpful in making adiagnosis or as a target for future therapy.

Clinical featuresThe major symptoms are bleeding and thrombosis. Other symptoms include epistaxis(nosebleeds) and bleeding from gums and gastrointestinal tract. One characteristicsymptom is throbbing and burning of the hands and feet due to the occlusion of smallarterioles by platelets (erythromelalgia). An enlarged spleen (splenomegaly) may befound on examination.

Diagnostic criteriaThe diagnosis of essential thrombocytosis requires the presence of a persistent

thrombocytosis of greater than 600 x109/L in the absence of an alternative cause.

The following revised diagnostic criteria for essential thrombocytosis were proposed in

2005 [7]. The diagnosis requires the presence of both A criteria together with B3 to B6,or of criterion A1 together with B1 to B6.

A1. Platelet count > 600 x 109/L for at least 2 monthsA2. Acquired V617F JAK2 mutation presentB1. No cause for a reactive thrombocytosis

normal inflammatory indices

B2. No evidence of iron deficiencystainable iron in the bone marrow or normal red cell mean corpuscularvolume

B3. No evidence of polycythemia vera

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hematocrit < midpoint of normal range or normal red cell mass in presenceof normal iron stores

B4. No evidence of chronic myeloid leukemia

But the Philadelphia chromosome may be present in up to 10% of cases. Patients withthe Philadelphia chromosome have a potential for the development of acute leukemia,especially acute lymphocytic leukemia.

B5. No evidence of myelofibrosisno collagen fibrosis and ≤ grade 2 reticulin fibrosis (using 0–4 scale)

B6. No evidence of a myelodysplastic syndromeno significant dysplasiano cytogenetic abnormalities suggestive of myelodysplasia

TreatmentNot all patients will require treatment at presentation. In those who are at increased riskof thrombosis or bleeding (older age, prior history of bleeding or thrombosis, or veryhigh platelet count), reduction of the platelet count to the normal range can be achievedusing hydroxyurea (also known as hydroxycarbamide), interferon-α or anagrelide. Low-dose aspirin is widely used to reduce the risk of thrombosis, but there may be anincreased risk of bleeding if aspirin is initiated while the platelet count is very high.

The PT1 study [8] compared hydroxyurea in combination with aspirin to anagrelide incombination with Aspirin as initial therapy for essential thrombocytosis. Hydroxyureawas superior, with lower risk of arterial thrombosis, lower risk of severe bleeding andlower risk of transformation to myelofibrosis (although the rate of venous thrombosiswas higher with hydroxycarbamide than with anagrelide).

In rare cases where patients have life-threatening complications, the platelet count canbe reduced rapidly using platelet apheresis (a procedure that removes platelets from theblood directly). ...

PrognosisEssential thrombocytosis is sometimes described as a slowly progressive disorder withlong asymptomatic periods punctuated by thrombotic or hemorrhagic events.

However, well-documented medical regimes can reduce and control the number ofplatelets, which reduces the risk of these thrombotic or haemorrhagic events. Thelifespan of a well controlled ET person is well within the expected range for a person ofsimilar age but without ET.

Special care related to pregnancyHydroxyurea and anagrelide are contraindicated during pregnancy and nursing. There iscurrent debate as to the safety of interferon during pregnancy and nursing. Essentialthrombocytosis can be linked with increased risk of spontaeous abortion or miscarriagein the first trimester of pregnancy. Throughout pregnancy, close monitoring of themother for thrombosis and placenta is recommended to ensure blood clots are caught.Post partum, often daily injections of low dose low molecular weight heparin (e.g.enoxaparin) are prescribed for several weeks as this is a period where the mother is athigher risk of developing a blood clot.

References1. ↑ Mesa R, Silverstein M, Jacobsen S, Wollan P, Tefferi A (1999). "[Expression error: Missing operand

for > Population-based incidence and survival figures in essential thrombocythemia and agnogenic myeloidmetaplasia: an Olmsted County Study, 1976-1995]". Am J Hematol 61 (1): 10–5. doi:10.1002/(SICI)1096-8652(199905)61:1<10::AID-AJH3>3.0.CO;2-I. PMID 10331505.

2. ↑ Kutti J, Ridell B (2001). "[Expression error: Missing operand for > Epidemiology of themyeloproliferative disorders: essential thrombocythaemia, polycythaemia vera and idiopathic myelofibrosis]".Pathol Biol (Paris) 49 (2): 164–6. PMID 11317963.

3. ↑ Hoffman: Hematology: Basic Principles and Practice, 4th ed., 2005 Churchill Livingstone, Chapter 71.

4. ↑ Kralovics R, Passamonti F, Buser AS, Teo SS, et al. (2005). "[Expression error: Missing operand for >A gain-of-function mutation of JAK2 in myeloproliferative disorders]". N Engl J Med 352 (17): 1779–90.doi:10.1056/NEJMoa051113. PMID 15858187.

5. ↑ Baxter EJ, Scott LM, Campbell PJ, et al. (2005). "Acquired mutation of the tyrosine kinase JAK2 inhuman myeloproliferative disorders". Lancet 365 (9464): 1054–61. doi:10.1016/S0140-6736(05)71142-9.PMID 15781101. http://linkinghub.elsevier.com/retrieve/pii/S0140-6736(05)71142-9.

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6. ↑ Levine RL, Wadleigh M, Cools J, et al. (2005). "Activating mutation in the tyrosine kinase JAK2 inpolycythemia vera, essential thrombocythemia, and myeloid metaplasia with myelofibrosis". Cancer Cell 7(4): 387–97. doi:10.1016/j.ccr.2005.03.023. PMID 15837627.http://linkinghub.elsevier.com/retrieve/pii/S1535-6108(05)00094-2.

7. ↑ Campbell PJ, Green AR (2005). "Management of polycythemia vera and essential thrombocythemia".Hematology Am Soc Hematol Educ Program 2005: 201–8. doi:10.1182/asheducation-2005.1.201. PMID16304381. http://www.asheducationbook.org/cgi/pmidlookup?view=long&pmid=16304381.

8. ↑ Harrison CN, Campbell PJ, Buck G, et al. (2005). "Hydroxyurea compared with anagrelide in high-riskessential thrombocythemia". N. Engl. J. Med. 353 (1): 33–45. doi:10.1056/NEJMoa043800. PMID16000354. http://content.nejm.org/cgi/pmidlookup?view=short&pmid=16000354&promo=ONFLNS19.

External linksCancerbackup Essential Thrombocytosis pageCMPD Education Foundation

Pathology: hematology · hematologic diseases of RBCs and megakaryocytes /MEP (D50-69,74, 280-287)

Categories:

Hematology | Blood disorders

HistoryView article history

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