Vascular neoplasms.

Vascular neoplasms in the broad sense represent a very common group of tumors or hamartomas that show great variability in gross appearance, microscopic appearance, and clinical course. Generally, neoplasms are composed of one cell type, but vascular neoplasms are collections of endothelial-lined tubes or tubules with connective tissue walls that may contain smooth muscle cells, pericytes, and nerve elements according to the specific tissues of origin. The classification of vascular neoplasms as outlined in this article attempts to delineate each tumor or hamartoma according to its histologic appearance and clinical behavior. The clinical course ranges from completely benign, self-involuting malformations such as the strawberry hemangioma to highly malignant angiosarcomas with their rapid growth and frequent metastases. Defects in the lymphatic system show gradations from simple lymphangiomas through lymphedema and lymphangiectasia, which can probably be explained by faulty embryologic development. Management of these lesions has been discussed, including brief descriptions of most of the currently accepted treatment methods for these frequently encountered clinical problems.