Three patients with a pseudomalignant cutaneous vascular disorder were seen. The name of intravenous atypical vascular proliferation is proposed for this condition, which is clinically characterized by the appearance of a small solitary nodule in the skin or mucosa of the face in an adult. The key microscopical feature is the presence of an exuberant endothelial proliferation within the distended lumina of medium-sized veins. We interpret this condition as being a new member of the group of related cutaneous diseases presently designated as "atypical vascular proliferation with inflammation." The disease should be differentiated from other proliferative conditions of cutaneous blood vessels, including pyogenic granuloma, hemangioma, Kaposi sarcoma, and angiosarcoma.
Rosai J, Akerman LR. Intravenous Atypical Vascular ProliferationA Cutaneous Lesion Simulating a Malignant Blood Vessel Tumor. Arch Dermatol. 1974;109(5):714-717. doi:10.1001/archderm.1974.01630050052012