Primary lymphoma bone

Primary bone lymphoma

definition

Primary bone lymphoma 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.

peak prevalence

The peak prevalence is among patients in the 6th to 7th decades of life.

forms

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.

most common sites

The femur is the most common site and is affected in 25% of cases. Vertebral involvement is not unusual and occurred in six of 24 cases (25%) reviewed in one study.

special groups

Primary multifocal osseous lymphoma: 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.

clinical manifestaions

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.

pathology

The diagnosis implies the exclusion of any evidence of nodal or disseminated disease on the basis of modern staging techniques. There are no reliable histological or immunocytologic features with which to distinguish primary bone lymphoma from secondary bone involvement. 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.

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.

prognosis

Distinguishing primary bone lymphoma from other bone tumors is important because PLB has a better response to therapy and a better prognosis.

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.