Bone involvement is a rare event in
lymphomas, except in patients with
adult T-cell leukemia/lymphoma associated with HTLVI. It is usually characterised by lytic bone lesions located in the metaphysis of long bones or in the axial skeleton. The occurrence of bone lesions reflects a progression of the disease affecting the prognosis that is related to
lymphoma histologic features and staging. Bone lesions may occur in some
lymphoproliferative disorders such as LLC or Waldenstrom's disease, or in
myeloproliferative disorders. They may reflect a progression to a more aggressive disorder with a worse prognosis. The treatment of
hematologic malignancies presenting with bone lesions and/or
hypercalcemia is similar to the treatment of the systemic disease. In primary
lymphomas of bone presenting with an isolated bone lesion, local treatment with
radiation therapy and/or surgical ablation is required, and
adjuvant chemotherapy may improve the prognosis of these located
lymphomas.
Glucocorticoid therapy and
bisphosphonates are effective in treating associated
hypercalcemia. Except for myeloma and ATL, the underlying mechanisms responsible for bone involvement in
hematologic malignancies remain poorly understood. The unusual occurrence of bone lesions in these diseases probably implies distinct pathogenic mechanisms, but one can speculate that an increased expression of RANK/RANKL, the common final pathway in
bone resorption, may be involved.