Vascular tumors are benign neoplasms , which result from proliferating endothelial cells . These lesions present during infancy or childhood, may affect any location, and exhibit postnatal growth . Local complications include bleeding, tissue destruction, and pain whereas systemic sequelae include thrombocytopenia, congestive heart failure , and death. Vascular tumors should be differentiated from vascular malformations , which present at birth, have a quiescent endothelium, and grow in proportion to the child. Together, vascular tumors and malformations comprise the field of vascular anomalies.