Difference between revisions of "Myeloproliferative neoplasms"

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'''Myeloproliferative neoplasms''', also '''myeloproliferative disorders''', are a group of indolent hematologic neoplasms characterized by clonal expansion of pluripotent hematopoietic progenitor.
'''Myeloproliferative neoplasms''', also '''myeloproliferative disorders''', are a group of indolent hematologic neoplasms characterized by clonal expansion of pluripotent hematopoietic progenitor.


These should '''not''' be confused with ''[[myelodysplastic syndromes]]'' (MDS).
These should '''not''' be confused with ''[[myelodysplastic syndromes]]'' (MDS), the main difference is that MPNs produce functional haematological cells detectable on a complete blood count, whereas in MDS, hematopoisis is ineffective and is characterised by cytopenias.


==Grouping==
==Grouping==
They include the following:<ref name=pmid15781101>{{cite journal |author=Baxter EJ, Scott LM, Campbell PJ, ''et al.'' |title=Acquired mutation of the tyrosine kinase JAK2 in human myeloproliferative disorders |journal=Lancet |volume=365 |issue=9464 |pages=1054–61 |year=2005 |pmid=15781101 |doi=10.1016/S0140-6736(05)71142-9 |url=}}</ref>
They include the following:<ref name=pmid15781101>{{cite journal |author=Baxter EJ, Scott LM, Campbell PJ, ''et al.'' |title=Acquired mutation of the tyrosine kinase JAK2 in human myeloproliferative disorders |journal=Lancet |volume=365 |issue=9464 |pages=1054–61 |year=2005 |pmid=15781101 |doi=10.1016/S0140-6736(05)71142-9 |url=}}</ref>
*Polycythemia vera.
*[[Chronic myeloid leukemia]]
*Essential thrombocythemia.
*[[Polycythemia vera]]
*Idiopathic myelofibrosis.
*[[Essential thrombocythemia]].
*[[Idiopathic myelofibrosis]].


==Clinic==
==Clinic==
* moderate to severe anemia
* increase in blood count(s), dependent on type of MPN
* anemia may occur in late stage disease or due leukemic transformation
* pale skin
* pale skin
* fatigue
* fatigue
* prolonged bleeding
* enlarged spleen  
* enlarged spleen  
* increased clotting
* increased clotting (i.e. thrombosis)
 
==Polycythemia vera==
*ICD-O: 9950/3
*Median age: 60 years.
*Median survival: >10years.
*Typical course:
**Prodromal stadium: Mild erythrocytosis.
**Polycythemic phase: Increased RBC count.
**Post-polycythemic ("spent") phase: Ineffective hematopoiesis, bone marrow fibrosis.
*Transformation to [[AML]] possible (2-3%).
 
===Morphology===
*Panmyelosis.
*Many megakaryocytes in bone marrow section.
*Increased cellularity of bone marrow (35-100%).
*Teardrop-RBC cells (dacrocytes) in late stage.
*Fibrosis (reticulin stain).
 
==Essential thrombocythaemia==
*ICD-O: 9962/3
*Median age: 55 years.
*Mostly asymptomatic.
*Indolent course, long-term survival. Life-threatening thromboembolic epsisodes.
 
===Morphology===
*Thrombocytosis.
*Bone marrow normo- to slightly hypercellular.
*Large hypersegmented megakaryocytes in bone-marrow.
*Usually no BM fibrosis.
 
==Images==
<gallery>
File:Thrombocytosis.jpg | Thrombocythemia. Peripheral blood (WC/Erhabor Osario)
File:Polycythemia_vera,_blood_smear.jpg | Polycythemia vera. Peripheral blood (WC/Orlandi Mourao)
File:Teardrop Cells smear 2009-09-22.JPG | Teardrop RBC cells in polycythemia vera. Peripheral blood (WC/AFIP)
File:Essential Thrombocythemia, Peripheral Blood (10189570483).jpg | Essential thrombocythemia. Peripheral blood (WC/Ed Uthman)
File:Essential thrombocythemia (2).jpg | Essential thrombocythemia. Bone marrow (WC/KGH)
</gallery>


==Molecular==
==Molecular==
* BCR-ABL1 negative (DDx: [[Leukemia]] (BCR-ABL1 positive))
* BCR-ABL1 negative (DDx: [[Leukemia]] (BCR-ABL1 positive))
* A specific JAK2 mutation (Val617Phe) in seen in a group of patients.<ref name=pmid15781101>{{cite journal |author=Baxter EJ, Scott LM, Campbell PJ, ''et al.'' |title=Acquired mutation of the tyrosine kinase JAK2 in human myeloproliferative disorders |journal=Lancet |volume=365 |issue=9464 |pages=1054–61 |year=2005 |pmid=15781101 |doi=10.1016/S0140-6736(05)71142-9 |url=}}</ref><ref name=pmid15860661>{{cite journal |author=Steensma DP, Dewald GW, Lasho TL, ''et al.'' |title=The JAK2 V617F activating tyrosine kinase mutation is an infrequent event in both "atypical" myeloproliferative disorders and myelodysplastic syndromes |journal=Blood |volume=106 |issue=4 |pages=1207–9 |year=2005 |month=August |pmid=15860661 |pmc=1895198 |doi=10.1182/blood-2005-03-1183 |url=}}</ref>
* A specific JAK2 mutation (Val617Phe) in seen in a group of patients.<ref name=pmid15781101>{{cite journal |author=Baxter EJ, Scott LM, Campbell PJ, ''et al.'' |title=Acquired mutation of the tyrosine kinase JAK2 in human myeloproliferative disorders |journal=Lancet |volume=365 |issue=9464 |pages=1054–61 |year=2005 |pmid=15781101 |doi=10.1016/S0140-6736(05)71142-9 |url=}}</ref><ref name=pmid15860661>{{cite journal |author=Steensma DP, Dewald GW, Lasho TL, ''et al.'' |title=The JAK2 V617F activating tyrosine kinase mutation is an infrequent event in both "atypical" myeloproliferative disorders and myelodysplastic syndromes |journal=Blood |volume=106 |issue=4 |pages=1207–9 |year=2005 |month=August |pmid=15860661 |pmc=1895198 |doi=10.1182/blood-2005-03-1183 |url=}}</ref>
**In JAK2-negative cases, CALR or MPL-Mutations are often found.<ref>{{Cite journal  | last1 = Nangalia | first1 = J. | last2 = Green | first2 = TR. | title = The evolving genomic landscape of myeloproliferative neoplasms. | journal = Hematology Am Soc Hematol Educ Program | volume = 2014 | issue = 1 | pages = 287-96 | month = Dec | year = 2014 | doi = 10.1182/asheducation-2014.1.287 | PMID = 25696868 }}</ref>


==See also==
==See also==

Latest revision as of 16:44, 26 May 2018

Myeloproliferative neoplasms, also myeloproliferative disorders, are a group of indolent hematologic neoplasms characterized by clonal expansion of pluripotent hematopoietic progenitor.

These should not be confused with myelodysplastic syndromes (MDS), the main difference is that MPNs produce functional haematological cells detectable on a complete blood count, whereas in MDS, hematopoisis is ineffective and is characterised by cytopenias.

Grouping

They include the following:[1]

Clinic

  • increase in blood count(s), dependent on type of MPN
  • anemia may occur in late stage disease or due leukemic transformation
  • pale skin
  • fatigue
  • enlarged spleen
  • increased clotting (i.e. thrombosis)

Polycythemia vera

  • ICD-O: 9950/3
  • Median age: 60 years.
  • Median survival: >10years.
  • Typical course:
    • Prodromal stadium: Mild erythrocytosis.
    • Polycythemic phase: Increased RBC count.
    • Post-polycythemic ("spent") phase: Ineffective hematopoiesis, bone marrow fibrosis.
  • Transformation to AML possible (2-3%).

Morphology

  • Panmyelosis.
  • Many megakaryocytes in bone marrow section.
  • Increased cellularity of bone marrow (35-100%).
  • Teardrop-RBC cells (dacrocytes) in late stage.
  • Fibrosis (reticulin stain).

Essential thrombocythaemia

  • ICD-O: 9962/3
  • Median age: 55 years.
  • Mostly asymptomatic.
  • Indolent course, long-term survival. Life-threatening thromboembolic epsisodes.

Morphology

  • Thrombocytosis.
  • Bone marrow normo- to slightly hypercellular.
  • Large hypersegmented megakaryocytes in bone-marrow.
  • Usually no BM fibrosis.

Images

Molecular

  • BCR-ABL1 negative (DDx: Leukemia (BCR-ABL1 positive))
  • A specific JAK2 mutation (Val617Phe) in seen in a group of patients.[1][2]
    • In JAK2-negative cases, CALR or MPL-Mutations are often found.[3]

See also

References

  1. 1.0 1.1 Baxter EJ, Scott LM, Campbell PJ, et al. (2005). "Acquired mutation of the tyrosine kinase JAK2 in human myeloproliferative disorders". Lancet 365 (9464): 1054–61. doi:10.1016/S0140-6736(05)71142-9. PMID 15781101.
  2. Steensma DP, Dewald GW, Lasho TL, et al. (August 2005). "The JAK2 V617F activating tyrosine kinase mutation is an infrequent event in both "atypical" myeloproliferative disorders and myelodysplastic syndromes". Blood 106 (4): 1207–9. doi:10.1182/blood-2005-03-1183. PMC 1895198. PMID 15860661. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1895198/.
  3. Nangalia, J.; Green, TR. (Dec 2014). "The evolving genomic landscape of myeloproliferative neoplasms.". Hematology Am Soc Hematol Educ Program 2014 (1): 287-96. doi:10.1182/asheducation-2014.1.287. PMID 25696868.