Imaging of lymphoma of the musculoskeletal system.

Imaging plays a crucial role in staging and the assessment of treatment response in patients who have lymphoma of the musculoskeletal system. This article reviews imaging features of lymphoma of bone, muscles, cutaneous, and subcutaneous tissue. At radiography, lymphoma of the bone is most commonly lytic, but the affected bone also can appear deceptively normal, even when a large tumor is present. At CT, lymphoma of muscle can be homogenous in attenuation, and it may not show contrast enhancement, making tumor detection more difficult. Post-treatment changes often are encountered at MR imaging and positron emission tomography, and when considered in light of the patient's therapy regimen (eg, radiation therapy and granulocyte-colony stimulating factor), they usually can be differentiated from tumor. Post-treatment changes include diffuse FDG uptake in marrow after chemotherapy, indicating rebound of normal marrow, and MR imaging signal abnormalities that may persist for anywhere from a few months to years after treatment.