Reza Rahbar Trevor J. McGill John B. Mulliken
The field of vascular anomalies has been obscured by its own bewildering descriptive and histologic nomenclature. Terminologic confusion has led to improper diagnosis, illogical treatment, and misdirected research efforts. The clinical presentation of vascularanomalies can be confusing, because they appear in the same color spectrum of blue, pink, and red. Often the same word has been used to describe entirely disparate vascular lesions ( Figure 174-1). Hemangioma has been applied as a generic term to describe various vascular lesions with distinctive natural histories and differing etiologies. The most common tumor of infancy, known as strawberry,capillary, cellular, or juvenile hemangioma, typically undergoes rapid growth during the first months of life, followed by slow, invariable involution. Port-wine stain, a lesion that never regresses, also has been called a capillary hemangioma. The term "cavernous hemangioma" continues to be incorrectly used for venous anomalies that never involute and gradually expand.
|Figure 174-1 Classification from old terminology to hemangioma or vascular malformation. (From Mulliken JB, Young AE: Vascular birthmarks: hemangiomas and malformations, Philadelphia, 1988, WB Saunders.) | |
In 1982, Mulliken and Glowacki presented a biologic classification based on clinical characteristics, natural history, and cellular features. This nosologic scheme cleared theclouds of confusion to reveal a multidisciplinary field involving several medical specialties, interventional radiologists, and surgeons. The initial classification was slightly modified and accepted at the 1996 biennial meeting of the International Society for the Study of Vascular Anomalies in Rome.[15a] On the basis of cellular kinetics and clinical behavior, there are two major categories ofvascular anomalies: tumors (lesions that arise by endothelial hyperplasia) and malformations (lesions that arise by dysmorphogenesis and exhibit normal endothelial turnover). Infantile hemangioma is the most common vascular tumor. It is a lesion that grows rapidly in early infancy and is characterized by endothelial proliferation and invariably undergoes slow regression. There are rare variantscalled Congenital Hemangioma defined as tumors that are fully developed at birth and do not exhibit the usual postnatal rapid proliferation.[3a] Other vascular tumors are the intermediate grade hemangioendotheliomas and high grade angiosarcomas. Vascular malformations are present at birth, although not always seen, and are characterized by a normal rate of endothelial cell turnover and growthcommensurate with the child ( Table 174-1 ). It is clinically useful to separate the vascular malformations into slow-flow anomalies (capillary, venous, lymphatic, or combined forms) and fast-flow anomalies (arteriovenous fistula [AVF] and arteriovenous malformation [AVM]) ( Figure 174-1 ).
Table 174-1 -- DISTINGUISHING CHARACTERISTICS
Hemangioma | Vascular Malformation |
Usually not seen atbirth | Always present at birth |
Gender: Female > Male | Equal gender distribution |
Race: More common in white | Equal between all races |
Rapid growth and slow regression | Grows proportionately with the child |
Firm and rubbery | Compressible |
Rarely involves bone or cartilage | May cause significant hypertrophy and distortion of craniofacial skeleton |
Infantile hemangioma is the most common tumor of infancy occurring in 4% to 10% of children by age one year. There is an increased incidence (23%) in prematures weighing less than 1000 g. Most infantile hemangiomas are not seen in the newborn nursery and appear during the first 6 weeks of life. Approximately one-third of these lesions will present at birth as a reddish macule,...