S8C19aP6a-1: This lesion was purported to be an example of erythema elevatum diutinum. It is a lobulated process with the lobules situated near the dermal-epidermal interface; this basic pattern is most reminiscent of the patterns seen in florid lesions of angiodermatitis. In the lobules, vessels are loosely spaced in a delicate, fibrous matrix.

S8C19aP6a-3: In this area, some of the vessels have thick walls and narrowed lumens; endothelial cells are swollen. There are clusters of extravasated red blood cells among the vessels. There are intra-mural and interstitial infiltrates of neutrophils. One vessel to the left of the center of the field shows a focal area of fibrinoid degeneration. These patterns are acceptable in the setting of angiodermatitis.

S8C19aP6a-4: Laminated, fibrinous lamellae are outlined by red arrows; these patterns have the qualities emphasized in the characterization of “toxic hyalin.” The vessels have thick walls; endothelial cells are swollen. There are focal infiltrates of neutrophils with fragments of nuclear debris near the top of the field on the left. The patterns can be accommodated in the collection of virtual images related to the histologic patterns of angiodermatitis. The diagnosis of EED is strongly influenced by the clinical presentation, so much so, that a variety of histologic patterns have been accommodated in its clinical definition.