Osteomyelofibrose

Primary myelofibrosis is a myeloproliferative neoplasm in which there is the replacement of bone marrow with collagenous connective tissue and progressive fibrosis. It is characterized by:

• extramedullary hematopoiesis
• progressive splenomegaly
• anemia
• variable change in the number of granulocytes and platelets including thrombocytopenia

Epidemiology

It usually affects the middle-aged to elderly, with a mean age of 60 years. The estimated prevalence is ~1:100,000.

Pathology

It is considered a chronic BCR-ABL1 (breakpoint cluster region-Abelson murine leukemia viral oncogene homologue 1)-negative myeloproliferative disorder .

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 .​

Radiographic features

Most radiological features are a result of extramedullary hematopoiesis and seen in many systems.

General

• lymphadenopathy

Musculoskeletal

• osteosclerosis
  • diffuse pattern
  • no bony architectural distortion
  • typical distribution:
    • axial skeleton
    • ribs
    • proximal humerus and femur
  • bone scan may give "superscan" appearance

Abdominal

• hepatomegaly
• splenomegaly: can be massive
  • some patients may also experience splenic infarcts 
• evidence of portal hypertension
  • from increased splenic blood flow
  • from portal flow obstruction from the sinusoidal hematopoietic proliferation

Cardiovascular

• may show evidence of congestive cardiac failure due to anemia

Treatment and prognosis

Prognosis is poor, with slow progression and death usually within 2-3 years. It can also transform into acute myeloid leukemia in a small number of patients .

Complications

• gout: from hyperuricemia due to increased hematopoietic turnover
• splenic rupture (rare)
• bleeding from thrombocytopenia (see case 8)

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

See also

• WHO classification of tumors of hematopoietic and lymphoid tissues

Siehe auch:

• Splenomegalie
• Sichelzellenanämie
• Tumoren des hinteren Mediastinums
• Thalassämie
• Bürstenschädel
• paraspinal mass
• thoracic paraspinal mass
• Hereditäre Sphärozytose
• diffuse skelettale Sklerosierung

und weiter:

• diffuse bony sclerosis (mnemonic)
• diffus hypointenses Knochenmarksignal in T1
• Knochenmarksveränderungen im MRT
• extramedulläre Hämatopoese
• Superscan Szintigraphie
• Knochenmark
• Knochenmarksveränderungen nach Bestrahlung
• Knochentumoren
• secondary gout
• secondary gout in primary myelofibrosis
• Myeloproliferative Neoplasien (MPN)