Cystic Hygroma and Lymphatic Malformations

Lymphatic malformations (LMs) are uncommon congenital low-flow vascular anomalies previously referred to as lymphangiomas or cystic hygromas. The terminology of vascular and lymphatic lesions needs to be standardized. Vascular and lymphatic lesions, in general, have been notoriously difficult for pathologists to diagnose and classify because of the large number of entities and their variants, and their frequently overlapping clinical and histopathologic features. This problem has been compounded by imprecise terminology with various names referring to the same lesion or, conversely, a particular term denoting different entities. Recently, the International Society for the Study of Vascular Anomalies (ISSVA), an organization comprised of specialists in various disciplines interested in vascular anomalies, approved a novel classification of vascular lesions that distinguishes malformations from tumors and provides an easily understood and concise nomenclature.