RT Book, Section A1 Macarthur, Kelly M. A1 Püttgen, Katherine A2 Kang, Sewon A2 Amagai, Masayuki A2 Bruckner, Anna L. A2 Enk, Alexander H. A2 Margolis, David J. A2 McMichael, Amy J. A2 Orringer, Jeffrey S. SR Print(0) ID 1161336744 T1 Vascular Tumors T2 Fitzpatrick's Dermatology, 9e YR 2019 FD 2019 PB McGraw-Hill Education PP New York, NY SN 9780071837798 LK dermatology.mhmedical.com/content.aspx?aid=1161336744 RD 2024/11/02 AB Vascular anomalies commonly present as birthmarks.1 Their classification has historically been problematic, with contradictory and confusing terminology and nomenclature. Although several classification schemes exist, the most widely accepted and comprehensive is the International Society for the Study of Vascular Anomalies (ISSVA) classification, updated in 2014, to incorporate clinical, imaging, histologic and (where known) genetic characteristics.1,2 Vascular anomalies are broadly divided into vascular malformations and vascular tumors.3 Vascular malformations (see Chap. 147) are errors of vascular morphogenesis whereas infantile hemangiomas and other vascular tumors are proliferative. Vascular tumors in the current ISSVA classification are subdivided into (a) benign, (b) locally aggressive or borderline, and (c) malignant; each has unique features based upon histology, biology, clinical appearance, behavior, prognosis, and treatment (Table 118-1).