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primary myelofibrosis

Monday 12 September 2005

fibrosis of the bone marrow; myeloid metaplasia, chronic idiopathic myelofibrosis, osteomyelofibrosis; primary myelofibrosis; PMF

Definition: Idiopathic myelofibrosis (IM), is a chronic myeloproliferative disorder (MPD) characterised by marrow fibrosis, extramedullary haematopoiesis and a leuco-erythroblastic picture of the peripheral blood.


- megakaryocytic hyperplasia and bizarre megakaryocytes in clusters in primary myelofibrosis (PMF)

- Massive splenomegaly (4.1 kg) in a patient with primitive myelofibrosis (PMF). Classic intrasinusoidal EMH & atypical megakaryocytic proliferation.

- bone marrow: primary myelofibrosis, prefibrotic stage; JAK2 pos

Digital slides

- UI:740 - Chronic idiopathic myelofibrosis.
- HPC:9669 (ICSFramework)
- HPC:283

Primary myelofibrosis is currently classified as a myeloproliferative disease in which the proliferation of an abnormal type of bone marrow stem cell results in fibrosis, or the replacement of the marrow with collagenous connective tissue fibers


- prefibrotic stage of primary myelofibrosis

  • bone marrow hyperplasia
  • predominance of megakaryocytic and erythroid precursors is observed
  • slight increase in reticulin staining
  • more typical of (adult) agnogenic myeloid metaplasia with myelofibrosis

- fibrotic stage of primary myelofibrosis

  • increased silver (reticulin) staining
  • marked fibrosis with pockets of cellularity that have fibroblasts and atypical megakaryoblasts


- trisomy 1q
- del(13q)
- del(20q)
- trisomy 8
- t(6;10) (q27;q11) (11248333)


- multiple myeloma (7644355)

See also

- bone marrow fibrosis
- myelofibrosis
- bone marrow anomalies
- bone marrow diseases
- bone marrow lesions
- megakaryocytes

  • megakaryocytic anomalies

- essential thrombocythemia


- Cox MC, Panetta P, Venditti A, Abruzzese E, Del Poeta G, Cantonetti M, Amadori S. New reciprocal translocation t(6;10) (q27;q11) associated with idiopathic myelofibrosis and eosinophilia. Leuk Res. 2001 Apr;25(4):349-51. PMID: 11248333