Myelofibrosis classification
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Mohamad Alkateb, MBBCh [2], Sujit Routray, M.D. [3]
Overview
Myelofibrosis is subclassified into primary and secondary types with the primary type being the more common and a high proportion of the cases resulting from mutations in the Janus kinase 2 (JAK2) gene. It can be secondary to a variety of malignant, non-malignant, and hematologic conditions. It can also be secondary to infections, toxins, and autoimmune diseases.
Classification
- Myelofibrosis is divided into two types:
- Primary
- Secondary
Primary Myelofibrosis
- The primary type, characterized by stem cell-derived clonal myeloproliferation, is often associated with mutations of the thrombopoietin receptor gene (MPL), the calreticulin (CALR) gene, or Janus kinase 2 (JAK2) gene with 90% of the patients carrying one of these mutations and the rest 10% are categorized as "triple-negative".[1][2]
- The 2016 World Health Organization (WHO) revised classification of myeloproliferative neoplasms (MPNs) defines 2 stages of primary myelofibrosis (PMF):
- Prefibrotic/early (pre-primary myelofibrosis) phase, characterized by granulocytic/megakaryocytic proliferation and lack of reticulin bone marrow fibrosis.[3][4]
- Overtly fibrotic (overt primary myelofibrosis) phase, characterized by bone marrow fibrosis, pancytopenia, higher blast count, extramedullary hematopoiesis, and unfavorable karyotype with a significantly shortened median survival.[3]
Secondary Myelofibrosis
- Myelofibrosis can be secondary to mulpltiple primary conditons such as:
- Malignancies and hematologic disorders (Hodgkin lymphoma, non-Hodgkin lymphoma, essential thrombocythemia, polycythemia vera, multiple myeloma, and malignancies with metastases to the bone)
- Toxins (Benzene, thorium dioxide, and x- or γ-radiation)
- Infections (Osteomyelitis, tuberculosis [TB])
- Autoimmune diseases (systemic lupus erythematosus [SLE], multiple sclerosis [MS])
References
- ↑ Tefferi A (December 2016). "Primary myelofibrosis: 2017 update on diagnosis, risk-stratification, and management". Am. J. Hematol. 91 (12): 1262–1271. doi:10.1002/ajh.24592. PMID 27870387.
- ↑ Barbui T, Thiele J, Gisslinger H, Kvasnicka HM, Vannucchi AM, Guglielmelli P, Orazi A, Tefferi A (February 2018). "The 2016 WHO classification and diagnostic criteria for myeloproliferative neoplasms: document summary and in-depth discussion". Blood Cancer J. 8 (2): 15. doi:10.1038/s41408-018-0054-y. PMC 5807384. PMID 29426921.
- ↑ 3.0 3.1 Guglielmelli P, Pacilli A, Rotunno G, Rumi E, Rosti V, Delaini F, Maffioli M, Fanelli T, Pancrazzi A, Pietra D, Salmoiraghi S, Mannarelli C, Franci A, Paoli C, Rambaldi A, Passamonti F, Barosi G, Barbui T, Cazzola M, Vannucchi AM (June 2017). "Presentation and outcome of patients with 2016 WHO diagnosis of prefibrotic and overt primary myelofibrosis". Blood. 129 (24): 3227–3236. doi:10.1182/blood-2017-01-761999. PMID 28351937.
- ↑ Rumi E, Cazzola M (February 2017). "Diagnosis, risk stratification, and response evaluation in classical myeloproliferative neoplasms". Blood. 129 (6): 680–692. doi:10.1182/blood-2016-10-695957. PMC 5335805. PMID 28028026.