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Part I: Vascular Tumors
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Vascular anomalies comprise 2 distinct disease entities—vascular tumors and vascular malformations. These entities differ in their biology, presentation, and natural history.
Hemangiomas are the most common vascular tumors of childhood. These lesions are subdivided into 2 broad classifications—hemangiomas of infancy and congenital hemangiomas.
Many patients with hemangiomas of infancy do not require treatment; however, those with life- or function-threatening lesions require pharmacologic and/or surgical interventions.
Hemangiomas of infancy sometimes arise in specific patterns (eg, cervicofacial and lumbosacral) that may be associated with airway or spinal cord involvement respectively.
Multiple cutaneous hemangiomas of infancy may be associated with visceral hemangiomas, particularly liver hemangiomas. Patients with this presentation should therefore undergo diagnostic screening.
Propranolol and corticosteroids are the mainstays of pharmacotherapy. Lasers are used primarily for the treatment of ulcerated hemangiomas and telangiectasias following involution.
Surgical excision is most commonly performed when hemangiomas present a threat to function or are associated with complications and do not respond to pharmacotherapy or other less-invasive alternatives, and when they cause periorbital or significant airway symptomatology and are unlikely to respond quickly to medical management.
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The field of vascular anomalies comprises a broad spectrum of lesions with dissimilar pathobiology and clinical behavior. Some of these lesions are easily recognizable and can be managed in a relatively straightforward fashion; however, many others are complex and often require the combined expertise of numerous specialists. Prior to the 1980s, progress in this field was stymied by the use of imprecise and inconsistent nomenclature, which led to confusion among professionals and poor communication between physicians and the research community. A seminal article by Mulliken and Glowaki (1982) marked a clear turning point. These authors proposed a nosologic system that designated vascular anomalies as either tumors or malformations, based on their clinical appearance, histopathologic features, and biologic behavior. Vascular tumors were defined as lesions arising by endothelial proliferation, whereas vascular malformations were thought to be developmental abnormalities that exhibit normal endothelial turnover. This system provided a basic framework that precipitated discussion among specialists and set the stage for demystifying the field. In 1996, the International Society for the Study of Vascular Anomalies reached a consensus on nosology, making only minor modifications to the classification system proposed more than a decade earlier. This revised system (Table 75-1) has been adopted by vascular anomaly experts worldwide and has had a crucial impact on progress in research and patient care.
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