Polycythemia vera classification
Polycythemia vera Microchapters
Polycythemia vera classification On the Web
American Roentgen Ray Society Images of Polycythemia vera classification
Polycythemia vera is a subtype of myeloproliferative neoplasm. Myeloproliferative neoplasm may be classified according to the World Health Organization into eight subtypes: chronic myelogenous leukemia, chronic neutrophilic leukemia, polycythemia vera, primary myelofibrosis, essential thrombocythemia, chronic eosinophilic leukemia, mastocytosis, and myeloproliferative neoplasms, unclassifiable. The classification of polycythemia is subdivided into primary polycythemia (which is a clonal process caused by the JAK2 mutation) and secondary polycythemia (which is a reactive process due to a state of chronic hypoxia). There are numerous causes of secondary polycythemia, and most of these causes are cardiopulmonary in origin.
Classification of myeloproliferative neoplasms
Polycythemia vera is a subtype of myeloproliferative neoplasm. Myeloproliferative neoplasm may be classified according to the World Health Organization into eight subtypes:
- Polycythemia vera: This is a condition of elevated hemoglobin and red blood cell mass caused by the JAK2 mutation.
- Essential thrombocythemia: This is a condition characterized by persistent elevation in platelets which increases the risk for thrombosis and hemorrhage. It is associated with a variety of mutations, such as JAK2, CALR, or MPL. These mutations are mutually exclusive. This condition can progress to myelofibrosis, which carries a poor prognosis.
- Chronic myelogenous leukemia, BCR-ABL1–positive: This condition is a common cause of chronic leukemia. The peripheral blood of patients with chronic myelogenous leukemia commonly shows elevation of white blood cell precursors at all stages of maturation, including metamyelocytes, and band cells. Treatment involves oral tyrosine kinase inhibitors such as imatinib, dasatinib, bosutinib, nilotinib, or ponatinib.
- Chronic myelogenous leukemia, BCR-ABL1–negative (atypical CML): This a condition that carries a high risk for transformation into acute myeloid leukemia. It is frequently underdiagnosed since the BCR-Abl translocation is not found. Treatment considerations include allogeneic stem cell transplantation.
- Chronic neutrophilic leukemia: This is a condition characterized by elevation of neutrophil count and is commonly caused by a mutation in the colony-stimulating factor 3R (CSF3R) gene.
- Primary myelofibrosis: This is a highly lethal condition in which the bone marrow is replaced by reticulin fibrosis, resulting in ineffective erythropoiesis. The etiology of this disease is abnormal megakaryocyte proliferation and excess production of transforming growth factor-beta (TGF-beta), which stimulates collagen deposition and fibrosis.
- Chronic eosinophilic leukemia, not otherwise specified: This condition is of unknown etiology. There is clonal proliferation of erythropoetic precursors which results in elevated eosinophils in the blood, bone marrow or peripheral tissues.
- Mastocytosis: This condition is caused by mast cell proliferation and results in symptoms of coughing, wheezing, gastrointestinal upset, anaphylaxis, and diarrhea. Patients typically have high levels of histamine (a peptide released by mast cells). Treatment usually involves imatinib. In 2016, it was discovered that the tyrosine kinase inhibitor midostaurin could effectively treat mastocytosis, including patients who harbor the D816V mutation for which imatinib is ineffective.
- Myeloproliferative neoplasms, unclassifiable.
There are no subcategories within polycythemia vera.
Classification of polycythemia
Polycythemia vera is a subcategory of polycythemia in general. Classification of polycythemia in general includes primary polycythemia and secondary polycythemia. Secondary polycythemia is due to chronic hypoxia which results in compensatory increase in erythrocyte production. Secondary polycythemia is therefore characterized by a reactive increase in erythrocyte production, rather than clonal proliferation of erythrocytes.
- Congestive heart failure: This condition is defined as the inability of the circulatory system to meet the metabolic demands of exercising tissues.
- Chronic obstructive pulmonary disease: This is a group of disorders including chronic bronchitis and emphysema.
- Interstitial lung disease: This condition is due to destruction of the pulmonary parenchyma, resulting in fibrosis and scarring of the lung tissue. There are a variety of causes.
- Smoking: Cigarette smoking can cause a state of chronic hypoxia.
- Obstructive sleep apnea: This condition is due to physical impediment of the airways, resulting temporary cessation of breathing at night. This causes a state of chronic hypoxia.
- High altitude residence: Elevated heights carry low oxygen content.
- Erythropoietin-secreting tumors:
- Vardiman JW, Thiele J, Arber DA, Brunning RD, Borowitz MJ, Porwit A; et al. (2009). "The 2008 revision of the World Health Organization (WHO) classification of myeloid neoplasms and acute leukemia: rationale and important changes". Blood. 114 (5): 937–51. doi:10.1182/blood-2009-03-209262. PMID 19357394.
- Valent P, Horny HP, Escribano L, Longley BJ, Li CY, Schwartz LB; et al. (2001). "Diagnostic criteria and classification of mastocytosis: a consensus proposal". Leuk Res. 25 (7): 603–25. PMID 11377686.
- Birgegård G (2015). "Advances and challenges in the management of essential thrombocythemia". Ther Adv Hematol. 6 (3): 142–56. doi:10.1177/2040620715580068. PMC 4480522. PMID 26137205.
- Beatrice JM, Garanito MP (2013). "Essential thrombocythemia: a rare disease in childhood". Rev Bras Hematol Hemoter. 35 (4): 287–9. doi:10.5581/1516-8484.20130059. PMC 3789436. PMID 24106449.
- Hayashi Y, Hirai H, Kamio N, Yao H, Yoshioka S, Miura Y; et al. (2013). "C/EBPβ promotes BCR-ABL-mediated myeloid expansion and leukemic stem cell exhaustion". Leukemia. 27 (3): 619–28. doi:10.1038/leu.2012.258. PMC 4506742. PMID 22948537.
- Gotlib J (2017). "How I treat atypical chronic myeloid leukemia". Blood. 129 (7): 838–845. doi:10.1182/blood-2016-08-693630. PMID 27899359.
- Maxson JE, Tyner JW (February 2017). "Genomics of chronic neutrophilic leukemia". Blood. 129 (6): 715–722. doi:10.1182/blood-2016-10-695981. PMC 5301820. PMID 28028025.
- Desterke C, Martinaud C, Ruzehaji N, Le Bousse-Kerdilès MC (2015). "Inflammation as a Keystone of Bone Marrow Stroma Alterations in Primary Myelofibrosis". Mediators Inflamm. 2015: 415024. doi:10.1155/2015/415024. PMC 4660030. PMID 26640324.
- Vidyadharan S, Joseph B, Nair SP (2016). "Chronic Eosinophilic Leukemia Presenting Predominantly with Cutaneous Manifestations". Indian J Dermatol. 61 (4): 437–9. doi:10.4103/0019-5154.185716. PMC 4966405. PMID 27512192.
- Valent P, Akin C, Hartmann K, Nilsson G, Reiter A, Hermine O; et al. (2017). "Advances in the Classification and Treatment of Mastocytosis: Current Status and Outlook toward the Future". Cancer Res. 77 (6): 1261–1270. doi:10.1158/0008-5472.CAN-16-2234. PMC 5354959. PMID 28254862.