Vascular tumors of infancy and childhood: beyond capillary hemangioma.

Vascular tumors of infancy and childhood represent a number of clinicopathologically distinct entities for which precise histopathological diagnosis is often essential in determining effective therapeutic approach. Unfortunately, pathologists and clinicians alike have traditionally tended to lump these tumors, in addition to small vessel vascular malformations, under overly generic terms like capillary hemangioma that do little, if anything, to guide proper clinical management. In the last decade this nosologic oversimplification has begun to wane as important new diagnostic tools and better understanding of etiology have evolved, facilitated by international recognition of the need for a multidisciplinary approach in dealing with these perplexing and often clinically devastating lesions. This article provides a brief historical perspective on this progress, and then focuses on the current clinical, histological, and immunophenotypical features that distinguish the major types of vascular tumors of infancy and childhood, also reviewing new evidence regarding their mechanisms of pathogenesis.