Primary myelofibrosis
Updates to Article Attributes
Myelofibrosis is a haematological disorder where there is the replacement of bone marrow with collagenous connective tissue and progressive fibrosis. It is also classified as a myeloproliferative disorder. It is characterised by:
- extramedullary hematopoiesis (EMH)
- progressive splenomegaly
- anaemia
- variable change in the number of granulocytes and platelets
Epidemiology
It usually affects the middle-aged to elderly (mean age 60 years6). The estimated prevalence is at ~1:100,000.
Pathology
Non-neoplastic fibroblasts produce collagen, which replaces normal bone marrow elements. This bone marrow fibrosis is a result of an inappropriate release of PDGF and TGF-ß from neoplastic megakaryocytes 8.
Subtypes
It can be broadly classified into:
- primary myelofibrosis, e.g. agnogenic myeloid metaplasia
- secondary myelofibrosis: marrow replacement from malignancy/toxins
Radiographic features
Most radiological features are a result of EMH and seen in many systems.
General
Musculoskeletal
-
osteosclerosis
- tends to be diffuse and there is a lack of architectural distortion
- frequent sites include
- axial skeleton
- ribs
- proximal humerus and femur
- bone scan may give "superscan" appearance
Abdominal
- hepatomegaly
- splenomegaly: can be massive
- evidence of portal hypertension 3
- from increased splenic blood flow
- from portal flow obstruction from the sinusoidal haematopoetic proliferation
Cardiovascular
- may show evidence of congestive cardiac failure due to anaemia 3
Treatment and prognosis
Prognosis is poor, with slow progression and death usually within 2-3 years. It can also transform into acute myeloid leukaemia (AML) in a small number of patients 10.
Complications
- gout: from hyperuricaemia due to increased haematopoietic turnover
- splenic rupture (rare) 9
Differential diagnosis
General differential considerations include:
- for musculoskeletal manifestations: consider the differential diagnosis of diffuse bony sclerosis
- for splenic manifestations: consider differential diagnosis for splenomegaly
-<li>for musculoskeletal manifestations: consider the <a href="/articles/diffuse-bony-sclerosis-differential-diagnosis">differential diagnosis of diffuse bony sclerosis</a>- +<li>for musculoskeletal manifestations: consider the <a href="/articles/diffuse-bone-sclerosis-differential">differential diagnosis of diffuse bony sclerosis</a>
Image 8 CT (C+ portal venous phase) ( create )
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