Trusted medical expertise in seconds.

Access 1,000+ clinical and preclinical articles. Find answers fast with the high-powered search feature and clinical tools.

Try free for 5 days
Evidence-based content, created and peer-reviewed by physicians. Read the disclaimer.

Myeloproliferative neoplasms

Last updated: March 8, 2021

Summarytoggle arrow icon

Myeloproliferative neoplasms (MPN) are a group of disorders characterized by a proliferation of malignant hematopoietic stem cells that belong to the myeloid cell lineage. The most clinically relevant MPN include chronic myeloid leukemia (CML), polycythemia vera (PV), primary myelofibrosis (PMF), and essential thrombocythemia (ET). An important etiological factor is the mutation of the Janus kinase-2 (JAK2) gene, which is present in almost all cases of PV and in approximately 50% of patients with ET and PMF. In contrast to the other subtypes, CML is characterized by a distinct translocation between chromosome 9 and 22 (BCR-ABL1 fusion gene). Each of these neoplasms has a typical pattern of cell proliferation: granulocytes are increased in CML, thrombocytes in ET, and all cell lines show increased proliferation in PV. PMF, on the other hand, shows an initial hyperproliferative phase, but eventually progresses to pancytopenia. All myeloproliferative neoplasms may lead to elevated uric acid levels and gout as a result of increased cellular breakdown. They are also associated with an increased risk of acute myeloid leukemia. Treatment involves hydroxyurea to reduce the cell count, polychemotherapy to halt the proliferation of malignant cells, and, in young patients, allogeneic stem cell transplantation.

According to the WHO classification, the following disorders belong to the group of myeloproliferative neoplasms:

With the exception of CML, all of these disorders show varying degrees of JAK2 mutations, which can be used as a diagnostic marker. The mutation causes the exchange of two amino acids (valinephenylalanine), which, in turn, results in dysregulation of the tyrosine kinase JAK2.

References:[1][2][3]

Overview

Clinical features

Diagnosis

Treatment

In myelofibrosis, RBCs shed tears (teardrop cells), because they have been forced out of the fibrosed bone marrow (extramedullary hematopoiesis).

Overview

Clinical features

Diagnostics [4]

ET is a diagnosis of exclusion; all other causes of thrombocytosis must be ruled out before the diagnosis can be made.

Differential diagnosis

Treatment

Complications

References:[7]

  1. Arber DA, Orazi A, Hasserjian R, et al. The 2016 revision to the World Health Organization classification of myeloid neoplasms and acute leukemia. Blood. 2016; 127 (20): p.2391-2405. doi: 10.1182/blood-2016-03-643544 . | Open in Read by QxMD
  2. Barbui T, Thiele J, Gisslinger H, et al. The 2016 WHO classification and diagnostic criteria for myeloproliferative neoplasms: document summary and in-depth discussion. Blood Cancer J. 2018; 8 (2): p.15. doi: 10.1038/s41408-018-0054-y . | Open in Read by QxMD
  3. Er T-K, Lin S-F, Chang J-G, et al. Detection of the JAK2 V617F missense mutation by high resolution melting analysis and its validation. Clin Chim Acta. 2009; 408 (1-2): p.39-44. doi: 10.1016/j.cca.2009.07.002 . | Open in Read by QxMD
  4. Mantadakis E, Tsalkidis A, Chatzimichael A. Thrombocytosis in childhood.. Indian Pediatr. 2008; 45 (8): p.669-677.
  5. Michiels JJ. Acquired von Willebrand Disease Due to Increasing Platelet Count Can Readily Explain the Paradox of Thrombosis and Bleeding in Thrombocythemia. Clinical and Applied Thrombosis/Hemostasis. 1999; 5 (3): p.147-151. doi: 10.1177/107602969900500301 . | Open in Read by QxMD
  6. Awada H, Voso M, Guglielmelli P, Gurnari C. Essential Thrombocythemia and Acquired von Willebrand Syndrome: The Shadowlands between Thrombosis and Bleeding. Cancers. 2020; 12 (7): p.1746. doi: 10.3390/cancers12071746 . | Open in Read by QxMD
  7. Chronic Myeloid Neoplasms - Myeloproliferative Neoplasms (MPN). http://www.pathologyoutlines.com/topic/myeloproliferativeCEL.html. Updated: March 14, 2018. Accessed: April 1, 2018.
  8. Herold G. Internal Medicine. Herold G ; 2014