Comparison of working formulation and REAL classification of non-Hodgkin's lymphoma: an analysis of 52 cases

Several classification systems have been proposed for non-Hodgkin's lymphoma (NHL), of which Working Formulation (WF) and the recent Revised European American Lymphoma (REAL) classification are the two most widely used. There have been only a few studies comparing the two classification systems. The present study was undertaken in view of the paucity of literature comparing the foresaid classifications.

This retrospective and prospective study included 52 cases of NHL. These cases were examined thoroughly with the routine stains and immunohistochemistry using a panel comprising CD45, CD20, CD45RO, CD5, and CD30. All the cases were classified using the WF as well as the REAL classification, taking into account the immunohistochemical results.

A wide age range and a slight male predominance were noted. The majority of cases were nodal, while 17% were extranodal. Using the WF, intermediate grade was the most common (65·38%), of which malignant lymphoma, diffuse large cell type and diffuse mixed small and large cell type were the two most frequent categories. On immunohistochemistry, 76·9% of the cases were B-cell immunophenotype. Of the various B-cell lymphomas, the most common was follicle center lymphoma and most common T-cell lymphoma was peripheral T-cell lymphoma. A comparison of the two classification systems revealed that T-cell neoplasms were grouped with B-cell lymphomas in the WF.

Though REAL classification requires a detailed immunohistochemical panel for thorough classification of all cases, the use of a basic panel of B- and T-cell markers allows the distinction between B- and T-cell lymphomas. Hence, REAL classification should be employed for categorization of NHL even in smaller centers with limited immunohistochemical panel.