Benign vascular tumors and tumor-like proliferations.

Appropriate nomenclature of benign vascular tumors and tumor-like conditions is problematic due to overlapping histologic features, limited understanding of the pathogenesis, and controversy regarding classification. Benign vascular anomalies are categorized into malformations, neoplasms, reactive proliferations, or ectasias based on their clinical behavior, currently accepted etiologies, and histopathology. We address controversies in the classification of some entities and also discuss recent immunohistochemical developments that have raised questions regarding the origin of certain vascular tumors. This comprehensive review focuses on the clinical presentation, behavior, associated conditions, histopathological findings, and differential diagnoses of benign vascular tumors and tumor-like conditions.