Histopathologic examination of the papule revealed a relatively well-circumscribed vascular proliferation consisting of dilated and angulated vascular channels lined by a single layer of widely spaced inconspicuous endothelial cells with only mild cytologic atypia. Focal branching of the vascular channels and projections of endothelium-covered stroma into the vascular lumina were seen. There was a mild associated chronic inflammatory infiltrate. The lesion was limited to the superficial to midreticular dermis and did not infiltrate the deep dermis or subcutaneous tissue.
A Papule Arising in Irradiated Breast Tissue—Diagnosis. Arch Dermatol. 2006;142(1):101-106. doi:10.1001/archderm.142.1.101-f