Cutaneous Vasculitis Update:

Figures 1-10

Figure 1. The size of vessel involvement is one histologic feature coupled with the predominate inflammatory cell that allow for classification of most common forms of cutaneous vasculitis. In general, Henoch Schönlein purpura (HSP) and cutaneous leukocytoclastic angiitis (CLA) (a.k.a. leukocytoclastic or hypersensitivity vasculitis) affect the superficial vessels of the skin where as polyarteritis nodosa (PAN), nodular vasculitis and giant cell arteritis (GCA) affect deep muscular vessels found at the dermal-subcutis interface and within the subcutis. Most other forms of vasculitis such as cryoglobulinemic vasculitis (CV) or antineutrophilic antibody associateded vasculitides such as Wegener’s vasculitis that affect multiple organs more diffusely affect the vascular tree. Note also how the depth and type of skin biopsy greatly influences the diagnostic yield.

Figure 2. Fibrinoid necrosis. The salient features of vasculitis are endothelial swelling, inflammatory infiltrates, and “fibrinoid necrosis” of the vessel wall. Fibrinoid necrosis, fibrin-like, is thought to be the most characteristic histopathological manifestation of vasculitis. Illustrated herein is multiple small vessel walls replaced by fibrinous material associated with scant lymphocytic infiltrates and extravasated red blood cells; the arrow highlights a necrotic endothelial cell.

Figure 3. Necrosis secondary to vasculitis. Epidermal infraction associated with a pan-dermal and sub cutaneous vasculitis. Note the involvement of the muscular artery (arrow). Infracts and ulcers are commonly associated with vasculitis affecting arteries.

Fig 4 Eccrine gland necrosis found at the base a cutaneous infarct due to Churg-Strauss syndrome. This finding is typically associated with coma- or pressure-induced blisters, but can be also be found in cutaneous vasculitis.

Figure 5. Neoangiogenesis: inflammation promoted angiogenesis or neo-vascularization found in some lesions of both cutaneous and systemic vasculitides may represent a double-edged sword compensating for ischemia one hand and promoting inflammation, thus maintaining vasculitis on the other (40, 41). Antibodies to CD31 highlight the numerous small vessels emanating from the adventia of this subcutaneous muscular artery involved by polyarteritis nodosa. Note that the lumen is obliterated by a fibrinous plug (arrow).

Fig 6 Reactive angioendotheliomatosis can be the consequence
of either vasculitis or a thrombo-occlusive disorder.
In this case, a lobular proliferation of capillaries in the dermis
with fibrin thrombi is evident. Diffuse or mixed lobular and
diffuse capillaries, reactive dermal fasciitis-like stromal changes,
and hobnail or epithelioid endothelial formation can be seen in
lesions of reactive angioendotheliomatosis

Figure 7. “Onion-skinning” of this small vessel, likely an arteriole found in the subcutaneous tissue in a patient with perniosis (chilblains) is a sign of primary vessel disease and a clue to the possible presence of vasculitis.

Figure 8. Perivascular nuclear debris. In the absence of marked fibrin deposits, the presence of perivascular nuclear debris or leukocytoclasis (circle) is clue to presence of vasculitis, in this case urticarial vasculitis. The arrow highlights focal fibrin deposits coating the lumen wall.

Fig 9 The healed scar of past arteritis in a patient with
rheumatoid vasculitis. Note the loss of the elastic lamina and
loss of vessel lumen by the fibrous scar.

Figure 10. Muscular vessel wall infiltration. Muscular vessel walls are not the site of diapedesis, so the finding of inflammatory cells within the adventia, media and/or intima is a sign of vasculitis. Illustrated here from a biopsy of a patient with an unclassified collagen vascular disease presenting with nodules and livedo reticularis is a muscular vessel (artery) whose endothelium is disrupted by lymphocytes (endothelialitis) and media and adventia harbor lymphocytes.

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