EORTC Classification for primary cutaneous lymphomas: A comparison with the R.E.A.L. Classification and the proposed WHO Classification

Primary cutaneous lymphomas differ significantly from their nodal equivalents in clinical behaviour and prognosis, and often require a different therapeutic approach. Since currently used classification systems for non-Hodgkin lymphomas do not or insufficiently recognize the special character of these lymphomas, primary cutaneous lymphomas are not uncommonly diagnosed incorrectly, and/or treated inappropriately with unnecessarily aggressive therapies. For that reason the Cutaneous Lymphoma Group of the European Organization for Research and Treament of Cancer (EORTC) has recently proposed a separate classification for the group of primary cutaneous lymphomas. The EORTC Classification is consistently based on a combination of clinical, histological, immunophenotypical and genetic criteria, and includes well-defined and recognizable disease entities. It contains a limited number of cutaneous T-cell lymphomas and cutaneous B-cell lymphomas, which comprise more than 95% of all primary cutaneous lymphomas. The clinical significance of this classification has been validated by long-term follow-up data of more than 800 patients with a primary cutaneous lymphoma. The basic principles of the EORTC Classification will be presented, and current controversies between the EORTC Classification on the one hand, and the R.E.A.L. Classification and the proposed WHO Classification on the other will be discussed.