Classification of cutaneous lymphomas - an update.

This review focuses on the evolution and conceptual aspects of classifications for cutaneous lymphomas. The World Health Organization/European Organization for Research and Treatment of Cancer (WHO/EORTC) classification and the WHO classification (4th edn, 2008) represent the first widely accepted classifications for lymphomas, in which the complete spectrum of primary cutaneous lymphomas is included. These classifications for primary cutaneous lymphomas define disease entities with distinct clinical, histological, immunophenotypic and genetic features. Final diagnosis is based on a synoptic integration of these features and implies clinicopathological correlation as a pivotal element of the diagnostic approach for primary cutaneous lymphomas. The entities, their definitions and diagnostic criteria of cutaneous lymphomas listed in the WHO/EORTC and WHO classifications are presented. Recent changes in the terminology and staging, practical implications and future perspectives are discussed.