Definition:

Infantile hemangiomas (IH) are neoplastic proliferations of vascular endothelial cells (ECs), characterized by a period of growth after birth, and eventual spontaneous involution. Forty percent of the lesions are associated with complications such as ulceration, bleeding, infection, pain, cardiac failure, airway compromise or eye impairment. Pathogenesis of IH is still shrouded in mystery even though various theories have been postulated to explain its origin. Recent studies provide strong evidence for the conclusion that the VEGF receptor 2 (VEGFR2) and Tumor Endothelial Marker 8 (TEM8) mutations represent risk factor mutations for hemangioma formation. In the proliferating phase, constitutive VEGFR2 signaling in ECs from hemangioma lesions affects downstream processes, including EC proliferation and migration, providing a mechanistic explanation for the rapid endothelial proliferation seen in hemangioma.