Primary lymphoma of the bone
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate-Editor-In-Chief: John Fani Srour, M.D.
Overview
Primary lymphoma of the bone (PLB) is an uncommon malignancy that accounts for less than 5% of all primary bone tumors. The majority of cases are of the non-Hodgkin type, with Hodgkin disease accounting for 6% of cases.
Classification
Although the original criteria for PLB described by Coley implied the involvement of a solitary bone, an expansion was suggested by Ostrowski et al in 1986 when they sub-classified osseous lymphoma into four groups. Group 2 includes cases in which more than one bone was affected but no nodal or visceral disease was present.
Pathophysiology
PLB most commonly are large cell or mixed small and large cell lymphomas of the B-cell lineage. On the basis of the current WHO classification, the majority of cases would be characterized as diffuse large B-cell lymphoma. T-cell primary bone lymphomas are rare and almost all lymphomas will express common leukocyte antigen and B-cell markers CD20 and CD79a.
The femur is the most common site and is affected in 25% of cases. Vertebral involvement is not unusual.
Epidemiology and Demographics
Age
The peak prevalence is among patients in the 6th to 7th decades of life.
Prognosis
Distinguishing primary bone lymphoma from other bone tumors is important because PLB has a better response to therapy and a better prognosis.
Diagnosis
Symptoms
Primary lymphoma of bone manifests with insidious bone pain, local swelling, a palpable mass, and systemic symptoms such as weight loss and fever. Vertebral involvement can cause radicular symptoms and, in some case, lead to compression of the spinal cord.
Imaging
The radiographic appearances of PLB are variable, and because the lesion can appear near normal on plain radiographs,bone scan or magnetic resonance imaging (MRI) should be used.
The presence of a solitary metadiaphyseal lesion with a layered periosteal reaction on plain radiographs and a soft-tissue mass on MRI is highly suggestive of lymphoma. However, diffuse multifocal osseous involvement and variable radiographic appearances of primary bone lymphoma are well known features.
Treatment
Treatment for PLB often involves radiation therapy to control the tumor in the affected bone. In certain instances, surgical intervention for control of the primary bone lesion may be desirable or necessary. Chemotherapeutic regimens are employed in cases of diffuse osseous involvement.