Hemangiomas are the most common benign tumors in infancy, occurring in up to 10% of children less than 1 year of age (Frieden et al., 1996). These lesions are two to three times more common in girls than boys (Gorlin et al., 1994; Pascual-Castroviejo et al, 1996). Sixty percent involve the head and neck (Esterly, 1995). Hemangiomas develop during the first few weeks of life but are not usually present at birth. They typically grow for months or rarely years because of rapid endothelial cell proliferation, then spontaneously involute (Mulliken & Glowacki, 1982). Some patients also develop cutaneous vascular malformations with a distribution similar to the hemangiomas. These lesions are composed of dysplastic vessels without cellular proliferation and never regress. They are subcategorized by their flow rate (high- or slow-flow malformations) and by their predominant anomalous channels (arteriovenous or lymphatic malformations).
Aside from the obvious cutaneous hemangiomas, anomalies often occur in the central nervous system, extracranial and intracranial arteries, heart, and aortic arch. Less frequently, hemangiomas occur in conjunction with skeletal changes, sternal malformations (Hersh et al., 1985), constitutional deformities (Burns et al., 1991), coarctation of the aorta (Pascual-Castroviejo et al., 1996), midabdominal raphé (Igarashi et al., 1985) or sacral and genitourinary defects. Hemangiomas involve not only the face, but also the pharynx, larynx, arms, shoulders, chest, back, mediastinum, limbs, trunk, genitalia, liver, gastrointestinal tract and other zones (Pascual-Castroviejo, 1985; Enjolras et al., 1990; Pascual-Castroviejo et al., 1996).