[Classification of vascular tumours and vascular malformations. Contribution of the ISSVA 2014/2018 classification].

The study of vascular anomalies, "angiomas", vascular tumours and vascular malformations is made difficult by the great variety and confusion of the names used in the literature for these diseases, some of which are rare. The great merit of the classification proposed by the International Society for the Study of Vascular Anomalies (ISSVA), adopted in 2014 and modified in 2018, is to propose a unambiguous nomenclature and to try to group these lesions in a logical way, contrasting with the lists of the usual "classifications". This classification is based on the distinction between proliferative lesions (tumours and reactive lesions) and those which are due to a congenital anomaly of vascular morphogenesis (vascular malformations). It incorporates recent data on the molecular causes of these diseases. The major groups of lesions recognised in this classification will be presented and some lesions of interest briefly discussed. This classification aims to be usable by all medical specialties and applicable to all tissues and organs, even if efforts are still needed to integrate organ-specific names in order to unify the nomenclature and eliminate confusion. Even if it does not solve all the problems in this complex field, the unification of the nomenclature is a major contribution of this classification and pathologists are strongly encouraged to refer to it in daily practice.