Primary cutaneous B-cell lymphoma: how useful is the new European Organization for Research and Treatment of Cancer (EORTC) classification?

Abstract

The classification of non-Hodgkin's lymphoma has undergone extensive revision in recent years, particularly with the development of immunophenotypic and genotypic criteria. While most general pathologists now rely upon the Revised European and American Classification of Lymphoma neoplasms (REAL), the cutaneous lymphoma project group of the European Organization for Research and Treatment of Cancer (EORTC) has put forward its own proposal for the classification of primary cutaneous lymphomas. While this is understandable in the context of cutaneous T-cell lymphoma, the EORTC classification of primary cutaneous B-cell lymphoma has proved more controversial: first, because chromosomal changes are largely excluded; secondly, because follicle centre cell lymphoma in the skin is imprecisely defined; and thirdly, because large B-cell lymphoma of the leg is included as a separate entity. This review identifies the main differences between the two systems of classifying B-cell lymphomas in the skin, and the areas of research required to clarify some of the outstanding issues. Pathologists are unlikely to adopt the EORTC proposals for B-cell neoplasms until these issues have been resolved.