Musculoskeletal involvement of leukaemia is not always apparent on imaging, although the disease is per se characterised by leukaemic infiltration of bone marrow.  

Leukaemia is a haematological neoplasm characterised by the overproduction of immature (blasts) or abnormally differentiated cells of the haematopoietic 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. 

Radiographic features

• manifestations of bone marrow replacement

  • although most plain radiographs appear normal, osteopenia is the most frequent finding ^1,2

  • radiolucent metaphyseal bands

    • paediatric patients, up to 40% of those with ALL ²

    • they represent the osteopenia in the most fast-growing parts of long bones ²

    • alternating radiolucent and radiodense metaphyseal lines are classically described in treated patients

  • periosteal reaction

  • coarse trabeculation

    • increased number of trabeculae can lead to an osteosclerotic appearance ², 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 ²

  • bone lytic lesions 

• intramuscular leukaemic infiltrates

  • rare ¹

  • 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 ¹

Skin involvement, known as leukaemia cutis, represents focal deposits of leukaemic cells in the epidermis, dermis, or subcutaneous tissues ²

See also

• systemic involvement of leukaemia 

  • CNS manifestations

  • thoracic manifestations 

  • testicular manifestations