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

<title/> Background: 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. Methods: 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. 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. Conclusion: 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. [ABSTRACT FROM AUTHOR]