Primary myelofibrosis


Appropriate Tests


Myelofibrosis is one of the myeloproliferative neoplasms (clonal stem cell disorders) in which increased marrow fibrosis is the dominant feature.

See also Myeloproliferative neoplasms

Full blood count, Blood film, White cell count differential (classically leucoerythroblastic anaemia, tear drop poikilocytes); bone marrow aspiration and trephine biopsy with cytogenetics. The Jak-2 mutation occurs in approx. 50% of patients with idiopathic myelofibrosis.

Calreticulin (CALR) mutations have been reported in up to 88% of patients with primary myelofibrosis who do not have a JAK-2 mutation.





Anaemia, especially


  • Bone marrow failure
    • Disease progression
    • Cytotoxic drugs


  • Hypersplenism


Bleeding, due to


  • Thrombocytopenia

Usually late in the course of the disease.

  • Platelet dysfunction

Platelet aggregation / platelet release reaction.


  • Acquired Von Willebrand disease



Klampfl T et al. N Engl J Med 2013; 369: 2379-2390.

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