S8C26P12ThromboticAngitides

S8C26P12-3: In this lesion of livedo vasculitis, vessels have thickened walls and swollen endothelium. Some of the vessels are slightly dilated and some show narrowed lumens. Arrows point to areas of fibrinoid necrosis. There is also a zone of fibrinoid necrosis near the margin of the field on the left. To the right of the center of the field, the perivascular infiltrates contain a sprinkling of neutrophils.

S8C26P12-4: The epidermis shows both necrosis and spongiotic changes, in the center and to the left of the field. The vessels are increased in number; the basic patterns are compatible with angiodermatitis . The vessels show fibrinoid necrosis (livedo vasculitis-like pattern) (PAS-alcian blue stain); the fibrinoid is PAS+. To the right, a portion of the epidermis is preserved and hyperplastic; the glycogen-rich, PAS+ cells in this area are representatives of the superficial unit of the epidermis.



S8C26P12-1: The vascular changes in this early (young) lesion of livedo vasculitis are subtle. The vessel in the upper portion of the reticular dermis has a narrowed lumen; it shows a zone of fibrinoid necrosis of its wall, to the left and above the lumen. There are minimal perivascular infiltrates. The neighboring dermis is edematous. To the left, in the interstitium of the reticular dermis, there are a few fragments of nuclear debris.

S8C26P12-2: Small vessels of the upper portion of the reticular dermis show thrombosis, and fibrinoid necrosis. There are perivascular collections of extravasated red blood cells (livedo vasculitis). The dark green arrows point to an area of early ischemic necrosis of the epidermis. A localized region of the basal layer and the superficial unit of the epidermis are relatively devoid of nuclei; in this same region, there is no recognizable basal unit (only a basal layer) of the epidermis.

S8C26P12-5: Several vessels in the mid- and lower portions of the dermis contain thrombi; they are occluded (blue arrows). The most superficial of these vessels is associated with extravasated red blood cells in the neighboring reticular dermis (anti-phospholipid syndrome; anti-cardiolipid syndrome; lupus anti-coagulant). The histologic features are those of a thrombotic disorder.

S8C26P12-6: At a higher magnification, three vessels are occluded. The material in the vessel, to the far left, has a proteinaceous quality; it is homogeneous, and relatively free of red blood cells.

S8C26P12-7: In this area, the lumen of the vessel is partially occluded; to the right and below, a lumen in preserved in a pattern of recanalization of a thrombus. The material in the lumen of the vessel has the qualities of a platelet and fibrin thrombus. The adventitia of the vessel shows activation of mesenchymal cells.

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