Histologic Diagnosis of Inflammatory Skin Diseases

Images

…t of a dense infiltrate of neutrophils, as well as absence of fibrin from the wall of venules, excludes a diagnosis of leukocytoclastic vasculitis. The findings in these photomicrographs are like those seen in a “butterfly blush.” 1…

Histologic Diagnosis of Inflammatory Skin Diseases

Identification of Basic Patterns: Skin: Vesicular Dermatitis

…may be (Fig. 5.275 A&B), and devoid completely of serum, fibrin, and inflammatory cells. In a frozen section of a disease that in a routine section exhibits clefts, no such spaces exist. Figure 5.267 A&B. Acantholysis versus acantholytic…

Histologic Diagnosis of Inflammatory Skin Diseases

Images

…thin nuclei in palisaded arrangement around a huge deposit of fibrin = Rheumatoid nodule ¬†Neutrophils and nuclear “dust” of neutrophils scattered in the zone encircled by histiocytes in palisaded array, it being replete with fibrin, is ty…

Histologic Diagnosis of Inflammatory Skin Diseases

Identification of Basic Patterns: Skin: Nodular and Diffuse Dermatitis

…from degenerated collagen [e.g., in necrobiosis lipoidica] to fibrin [e.g., in rheumatoid nodule], the changes in the center of a palisade presumably resulting from a “mini-infarct”), and one in which epithelioid histiocytes appear to be…

Histologic Diagnosis of Inflammatory Skin Diseases

Images

…a palisade around a focus that consists of deposits of mucin, fibrin, and necrosis of inflammatory cells = Granuloma annulare, subcutaneous The fundamental attributes morphologic of granuloma annulare are the same in the subcutaneous fat as they are…

Histologic Diagnosis of Inflammatory Skin Diseases

Errors and Reasons

…rtifactual character are recognizable morphologically. Error: Fibrinoid necrosis, fibrinoid degeneration, and fibrinoid are accurate characterizations of a particular finding by conventional microscopy. Reason: Fibrinoid simply is fibrin. Error: Fibr…

Histologic Diagnosis of Inflammatory Skin Diseases

Applicable Terms

…pyoderma vegetans. Necrotic keratocytes, parakeratotic cells, fibrin, and bacteria may be found in crusts of any kind, but particularly in those termed vegetations. Figure 3.12 Crust. DEGENERATION [L. degenerare (to decline in quality)]: In classi…

Histologic Diagnosis of Inflammatory Skin Diseases

Images

…0.35.1C + 10.35.1D = Factitious dermatitis¬†Each focus of fibrin represents a site where a needle penetrated the skin and around each of those foci is a foreign body reaction, the histiocytes being arrayed in a palisade. In the lower half of the…

Histologic Diagnosis of Inflammatory Skin Diseases

Images

…n the upper part of the dermis is so striking. The absence of fibrin from the wall of venules and the presence of such prominent edema exclude the possibility of leukocytoclastic vasculitis. 10.102.2A: Nodular dermatitis, neutrophils predominan…

Histologic Diagnosis of Inflammatory Skin Diseases

Images

…2.2A: Vasculitis, small-vessel, neutrophilic + 10.62.2B : Fibrin in the wall of some venules, thrombi in the lumen of others, and fibrin and thrombi together in still others; perivascular and interstitial infiltrate of neutrophils mostly = Livedo…