Hemangiomas

The lack of standardized terminology has been a significant obstacle to a clear understanding of vascular lesions. Although the classic hemangioma undergoes involution with time, the term hemangioma has been used generically to include various vascular lesions, such as port-wine stains or venous malformations. Hemangiomas differ significantly from these other vascular lesions with regard to their clinical and histologic characteristics as well as long-term prognosis. In 1982, Mulliken and Glowacki published a classification scheme that simplified the nomenclature of vascular anomalies. It is based on the cellular biology and natural history of these lesions. The authors divide vascular birthmarks into two groups: hemangiomas and vascular malformations. Definitions HEMANGIOMAS Hemangiomas are defined as benign neoplasms composed of proliferative and hyperplastic vascular endothelium. They are dynamic lesions that demonstrate rapid postnatal growth followed by slow involution. Resolution is associated with diminished cellularity and fibrosis. Hemangiomas are subdivided into three types: superficial, deep, and mixed. Superficial hemangiomas, otherwise referred to as capillary or strawberry hemangiomas, lie in the papillary (upper) dermis. Deep lesions, also called cavernous, hypodermal, or subcutaneous hemangiomas, lie in the reticular (lower) dermis, fat, and muscle. Hemangiomas also may be mixed, having both superficial and deep components. Whether capillary hemangiomas differ histologically from cavernous lesions is controversial.