S8C36P22Wegener



S8C36P22-1: The epidermis shows hyperplasia of the superficial unit with pallor of the cytoplasm of keratinocytes. There is epidermal intra-cellular edema (perinuclear vacuoles). Some of the pallor is a degenerative change, related to early ishemic necrosis. There are lytic defects at the tips of some of the dermal papillae; they contain neutrophils and extravasated red blood cells. Vessels in the upper portion of the reticular dermis and in the dermal papillae show fibrinoid necrosis and thrombosis. There are collections of extravasated red blood cells in the papillary dermis. The vessel, to the left in the papillary dermis, is shown at a higher magnification in S8C36P22-3 (Wegener’s granulomatosis).


S8C36P22-2: In this field, the papillary dermis is edematous; the epidermis has separated from the dermis. Vessels of the papillary dermis show thrombosis and fibrinoid necrosis. There are perivascular infiltrates of neutrophils with leukocytoclasia. There are perivascular collections of extravasated red blood cells. In the areas outlined by blue arrows, histiocytes are arranged in palisades about vessels. The vessel to the left shows a thin luminal deposit of fibrinoid; its lumen is dilated. A multinucleated giant cell is adjacent to the smaller of the two vessels that are outlined by blue arrows (see S8C36P22-4) ( Wegener’s granulomatosis).

S8C36P22-3: At a higher magnification, the vessel shows fibrinoid necrosis of its wall. The perivascular space is widened (edematous). Neutrophils have infiltrated the interstitium of the reticular dermis; there are fragments of nuclear debris (the patterns can be easily dismissed as a leukocytoclastic angiitis). In addition, there is a high component of plump histiocytes (blue arrows) in the adventitia of the affected vessel (leukocytoclastic neutrophilic and granulomatous angiitis in the setting of Wegener’s granulomatosis).

S8C36P22-4: The dilated vessel to the left shows fibrinoid necrosis and palisades of histiocytes; it is micro-aneurysmal. Beyond the adventitia, the interstitium of the reticular dermis contains infiltrates of neutrophils and fragments of nuclear debris. In this example of Wegener’s granulomatosis, even the affected, small cutaneous vessels show granulomatous changes.

S8C36P22-5: In this pulmonary “granuloma” of Wegener’s granulomatosis, there are zonal patterns with pale, fibrous and necrotic areas that are irregular in outline. Histiocytes and lymphocytes form palisades at the margins of the pale zones. There is a prominence of bright red, loosely spaced, collagenous lamellae in scattered arrays. These fibrous lamellae should be compared with the parallel lamellae that are often a feature of granuloma faciale and erythema elevatum diutinum (EED).



	S8C36P22-6: In this area of a pulmonary granuloma of Wegener’s granulomatosis, the acidophilic zone of necrosis is somewhat stellate in outline; the lesion, in toto, makes a fairly good “palisaded granuloma.” Histiocytes and occasional giant cells are arranged in palisades about the zone of necrosis. The adjacent tissue is fibrotic; it contains infiltrates of chronic inflammatory cells. There is some preservation of architectural patterns in the zone of necrosis. The outlines of collagen bundles are preserved in the zone of acidophilic necrosis. The patterns offer support for the interpretation that fibrosis preceeded the necrosis in this area.

S8C36P22-7: In this area, a zone of fibrinoid necrosis is represented on the right at the top of the field. The next zone to the left is composed of loosely cellular fibrous tissue. In this tissue, some of the cells form fascicular patterns; the fascicles intersect to form starburst patterns (a “fibro-histiocytic” quality). At the left margin of the fibro-histiocytic component, histiocytes form ill-defined palisades. Eosinophils are prominent in the inflammatory infiltrates. It is of interest to compare these patterns to those seen in some examples of erythema elevatum diutinum (S8C19bP6b-5) ( Wegener’s granulomatosis).

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