Leukemia (musculoskeletal involvement)

Musculoskeletal involvement of leukemia is not always apparent on imaging, although the disease is per se characterized by the bone marrow infiltration.  
Leukemia is a hematological neoplasm characterized by the overproduction of immature (blasts) or abnormally differentiated cells of the hematopoietic system in the bone marrow that often, but not always, extends into the peripheral blood and, therefore, may involve multiple organs, including also the muscles and soft tissues.

  • manifestations of bone marrow replacement
    • although most plain radiographs appear normal, osteopenia is the most frequent finding
    • radiolucent metaphyseal bands
    • periosteal reaction
    • coarse trabeculation
      • increased number of trabeculae can lead to an osteosclerotic appearance , which is commonly seen as a result of secondary myelofibrosis 
    • vertebral body collapse (vertebra plana
    • MRI
      • T1: diffuse low signal
      • T2: increased signal
      • T1 C+ (Gd): diffuse enhancement
  • bone involvement without marrow involvement
    • can be seen due to direct invasion or haematogenous seeding
    • bone lytic lesions 
  • intramuscular leukemic infiltrates
    • rare
    • focal soft tissue deposits forming mass-like lesion within the muscles 
    • usually demonstrates contrast enhancement 
    • iso signal compared to the background muscle on T1 and increased signal on T2 weighted images
  • leukemia cutis
    • focal deposits of leukemic cells in the epidermis, dermis, or subcutaneous tissues

See also