Vascular Malformations

Epidemiology

The classification of vascular lesions of the extracranial head and neck developed by Mulliken and Glowacki is based on their biological and clinical characteristics. In the past, different terms have been used by different specialties to describe the same lesions. This classification system attempts to unify the nomenclature and improve the understanding of these complex lesions. Vascular lesions are classified as malformations and hemangiomas. Malformations are further divided based on their histology and include capillary, venous, arteriovenous (arterial, fistulae), lymphatic, and mixed. Hemangiomas are further subdivided based on their growth phase, which consists of a proliferating and involuting phase.

Clinical Findings

Vascular malformations are always present at birth. Enlargement of these lesions is due to growth of the child rather than proliferation of the endothelial cells that compose the lesion. These lesions do not undergo spontaneous involution. The incidence in males is equal to that in females.

Hemangiomas typically present in neonates or in early infancy. These lesions enlarge by endothelial proliferation and begin to undergo spontaneous involution after the first year of life. Hemangiomas are more common in females (M:F ratio = 1:5).