II. INTRODUCTION
The International Society for the Study of Vascular Anomalies (ISSVA)
initially proposed, and continues to update, a widely held
classification system for approaching vascular anomalies. There are two
broad general groups: 1) tumors (which are proliferative in nature) and
2) malformations (which are non-proliferative in nature). Simple
malformations refer to capillary (CM), lymphatic (LM), venous (VM), or
arteriovenous malformations (AVM) (1). Malformations can be localized to
a specific body area, or more extensive in nature. Vascular
malformations are thought to arise from somatic mutations acquired
during fetal development (2). Most will present at birth or in early
childhood (3). They exhibit a wide variability of clinical impact
ranging from asymptomatic lesions, to cosmetic concerns, and even
life-threatening symptoms due to close proximity to vital structures
such as the airway or lungs (4,5). In general, clinical evaluation and
imaging is usually diagnostic, but occasionally biopsy is needed if
atypical features are present. Biopsy is not without risk, as lesions
are prone to bleed. Immuno-histochemical markers and examination of
vascular architecture can clarify diagnosis. CD34 confirms endothelial
origin (6), while D2-40 (podoplanin) and LYVE-1 are associated with
lymphatic vessels. CD31 and SMA stain positive in VMs (7). Genetic
analysis of tissue will become more important as options for targeted
therapy become increasingly available. In this review, we describe four
cases and examine the clinical features, diagnostic options, and
management strategies of simple, localized malformations. As a
multi-disciplinary team is often needed to manage these complex
patients, we will examine the role of multiple disciplines, including
the pediatric hematologist and oncologist, in the care of patients with
vascular malformations.