S12C15P5-Granuloma -CT disease



S12C15P5-1: In the center of the field, a dermal defect contains infiltrates of inflammatory cells and basophilic debris. Histiocytes form palisades about the defect (small, palisaded granuloma of collagen-vascular disease).

S12C15P5-2: This palisaded granuloma shows a central, irregular zone of necrosis; the reacting cells, among the altered collagen bundles, are neutrophils. Disintegration of these cells has imparted a basophilia to the zone of necrosis. The lesion is stellate in outline. Histiocytes form palisades at the periphery of the zone of necrosis (palisaded granuloma of collagen-vascular disease; granulomatous interstitial dermatitis of immune complex disease; palisaded neutrophilic and granulomatous dermatitis). The lesion has qualities of a small “rheumatoid nodule.” Collagen bundles in the zone of necrosis are swollen and more brightly acidophilic (they are “necrotic”). Viable connective tissue cells are not among the altered collagen bundles in the zone of necrosis. Collagen, although admittedly extra-cellular, has a cell-dependent vitality; in the absence of supporting mesenchymal cells, a characterization of the altered collagen bundles as being “necrotic” is appropriate. Continuity between collagen bundles in the zone of necrosis and bundles of the neighboring dermis is lost at the interface between the two. The connective tissue of the zone of necrosis is “dead.” It would entail something more than a simple migration of connective tissue cells into the defect to restore vitality. It would require removal of the “dead” connective tissue and an inlay of new fibrous tissue in the defect. It is proper to speak of “necrotic” collagen bundles. Collagen bundles have a vitality that is dependent on the preservation of native connective tissue cells among the bundles.

S12C15P5-3: The basophilic debris in the zone of necrosis has been produced by the breakdown of neutrophils. Histiocytes form prominent palisades at the periphery of the zone of necrosis. Partly digested, “necrotic” collagen bundles also are present in the inflammatory debris of the defect.

S12C15P5-4: In this lesion of Wegener’s granulomatosis involving the upper respiratory tract, vessels are tortuous. They have thickened walls and are outlined by concentric fibrous lamellae. There are perivascular infiltrates of lymphoid cells. The background tissue is fibrotic.

S12C15P5-5: Small, thick-walled vessels are associated with prominent infiltrates of inflammatory cells (Wegener’s granulomatosis). Eosinophils are prominent in the infiltrates.

S12C15P5-6: The perivascular infiltrates are pleomorphic. Connective tissue cells are activated. The relationships are reminiscent of changes in lesions of granuloma faciale.

S12C15P5-7: Centrally, a small vessel has a thickened wall and a narrowed lumen. Histiocytes are arranged in palisades about the altered vessel (granulomatous angiitis) (Wegener’s granulomatosis).

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