Musculoskeletal involvement of leukemia is not always apparent on imaging, although the disease is per se characterized by leukemic infiltration of bone marrow.  

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. 

Radiographic features

• manifestations of bone marrow replacement

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

  • radiolucent metaphyseal bands

    • pediatric 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 hematogenous seeding ²

  • bone lytic lesions 

• intramuscular leukemic 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 leukemia cutis, represents focal deposits of leukemic cells in the epidermis, dermis, or subcutaneous tissues ²

See also

• systemic involvement of leukemia 

  • CNS manifestations

  • thoracic manifestations 

  • testicular manifestations