CB/CC diffuse lymphoma: A distinct subtype of non-Hodgkin's lymphoma? A study of 1593 patients from a Danish population-based registry

Between 1983 and 1993, 3165 cases of non-Hodgkin's lymphoma (NHL) were reported to the West Danish Lymphoma Registry (LYFO). Out of these, 148 (4.7%) were of the CB/CC diffuse subtype according to the Kiel classification. However, in the new European American NHL consensus classification (REAL, 1994), CB/CC diffuse lymphoma was categorized as a provisional subtype only. In the LYFO material, death-probability curves show a significantly shorter survival in CB/CC diffuse than in CB/CC follicular. In order to detect further possible differences between CB/CC diffuse and other NHL subtypes, a number of clinical parameters at presentation were analyzed in a subset of five types of lymphoma. This subset included 148 cases of CB/CC diffuse, 435 cases of CB/CC follicular, 667 cases of CB diffuse, 202 cases of CC diffuse, and 131 cases of peripheral T-cell lymphoma. Using logistic regression analysis, significant differences could be demonstrated between CB/CC diffuse and the four other subtypes as regards sex ratio, age distribution, and sites of both nodal and extranodal involvement. These findings indicate that CB/CC diffuse has a distinct clinical phenotype and imply the existence of real biological differences between CB/CC diffuse and other subtypes of lymphoma.