Primary lymphoma of bone: extranodal lymphoma with favourable survival independent of germinal centre, post-germinal centre or indeterminate phenotype.

AIMS

To determine prognostic significance of immunohistochemical markers and investigate possible germinal centre (GC) derivation in primary lymphoma of bone (PLB).

METHODS

Immunohistochemical expression of BCL-6, CD10, BCL-2, p53, CD30, CD44 and MUM-1 was studied in 36 patients with PLB. All cases were clinically staged and cases of secondary bone involvement of primary nodal lymphomas were excluded, prior to immunostaining. Clinical charts were reviewed for clinical symptoms and therapy given; survival post-biopsy was calculated.

RESULTS

All patients presented with pain and a palpable mass. The majority showed centroblastic-multilobated morphology; half of the cases (19/36) had a GC phenotype (CD10+BCL-6+ or CD10-BCL-6+MUM-1-), whereas 8/36 cases had a non-GC phenotype (CD10-BCL-6- or CD10-BCL-6+MUM-1+). Nine cases were of indeterminate phenotype (CD10-BCL-6+; MUM-1 not available). Eight of 22 evaluated patient samples showed immunoreactivity for MUM-1. Most patients (31/36) received combination therapy in the form of polychemotherapy and radiotherapy. The five-year overall survival was 75%. No significant difference in survival was found between the three different tumour phenotypes, or for the tested antigens individually. Age at presentation and stage of disease had a significant influence on five-year overall survival. Survival rates were 90% for the patients <60 years of age and 40% for those > or =60 years. Survival rates were 90% for stage I and 41% for stage IV.

CONCLUSION

This study illustrates the homogeneity of PLB. The majority of cases are of the GC phenotype which has a favourable prognosis.