Diffuse large B cell lymphoma with an interfollicular pattern of proliferation shows a favourable prognosis: a study of the Osaka Lymphoma Study Group.

AIMS

Diffuse large B cell lymphoma (DLBCL) occasionally shows an interfollicular pattern of proliferation (DLBCL-IF) preserving lymphoid follicles. In this study, clinicopathological findings in 31 cases of DLBCL-IF were analysed.

METHODS AND RESULTS

The study group comprised 20 males and 11 females, with ages ranging from 41 to 87 (median 69) years. The primary site was lymph node in 25 cases, and unknown in six due to advanced stage at diagnosis. Eight cases were clinical Stage I, 10 were Stage II, four Stage III, and nine Stage IV. A polymorphous pattern of proliferation containing large B cells and inflammatory cells was found in about 60% of cases. The overall survival rate of the DLBCL-IF patients was better than that of a DLBCL control group (log-rank test; P < 0.05). Multivariate analysis revealed that an interfollicular pattern of proliferation showed marginal significance for favourable prognosis (P = 0.069). Immunohistochemical double staining with antibodies for HLA-DR/CD68 (markers for M1-tumour-associated macrophage [M1-TAM]) or CD163/CD68 (M2-TAM) revealed that all DLBCL-IF patients with a low M2 count were alive at the end of observation.

CONCLUSIONS

These findings suggest that DLBCL-IF is a clinicopathological entity distinct from ordinary DLBCL. The possible origin of tumour cells in DLBCL-IF from marginal zone B cells is discussed.