Figure 2.1 Acute Spongiotic Dermatitis. The stratum corneum is large normal, and there is intraepidermal edema (spongiosis) and a superfici perivascular inflammatory infiltrate

Figure 2.2 Subacute Spongiotic Dermatitis. The epidermis is acanthotic and spongiotic with overlying parakeratosis

 

Figure 2.3 Chronic Spongiotic Dermatitis. There is compact hyper- keratosis, a thickened granular layer, minimal spongiosis, and a sparse perivascular infiltrate

 

Figure 2.4 Langerhans Cell Microabscess. Intraepidermal collections of Langerhans cells are often found in allergic contact dermatitis

Figure 2.5 Stasis Dermatitis. Within the superficial dermis there is a lobular proliferation of relatively thick-walled vessels with hemorrhage and overlying spongiosis in the epidermis

Figure 2.6 Typical Appearance of Psoriasis. Note the engorgement of papillae and Munro microabscesses

 

Figure 2.7 Guttate Psoriasis. Note the discrete mound of parakeratosis with overlying collections of neutrophils

 

Figure 2.8 Lichen Simplex Chronicus. There is compact hyperkeratosis overlying an acanthotic epidermis with a thickened granular layer. Vertically oriented, thickened collagen bundles are present in the superficial dermis

 

Figure 2.9 Erythema Multiforme. There is interface change with basal vacuolization, numerous dyskeratotic keratinocytes, and a sparse peri- vascular infiltrate

 

Figure 2.10 Microscopic changes of acute graft-versus-host reaction

 

Figure 2.11 Extensive facial lesions of chronic discoid lupus erythematosus

  

Figure 2.12 Lesion of chronic discoid lupus erythematosus showing hyperkeratosis and interface change with hydropic degeneration along basal layer

  

Figure 2.13 Clinical Appearance of Lichen Planus Affecting the Dorsum of the Hand. One of the lesions has been biopsied

  

Figure 2.14 Microscopic Appearance of Lichen Planus. There is orthotopic hyperkeratosis, hypergranulosis, basal vacuolization, and a band-like inflammatory infiltrate with melanophages

  

Figure 2.15 Lichenoid Tissue Reaction. Lichenoid drug reactions resemble lichen planus, but typically have parakeratosis, which is usually absent in lichen planus. (Courtesy of Dr Fabio Facchetti, Brescia, Italy.)

  

Figure 2.16 Fixed Drug Eruption. The infiltrate is rich in eosinophils and is accompanied by necrotic keratinocytes

  

Figure 2.17 Pityriasis Lichenoides Et Varioliformis Acuta. There is interface change with basal vacuolization and a superficial and deep lymphocytic infiltrate with papillary dermal hemorrhage

  

Figure 2.18 Morbilliform Drug Eruption. The epidermis is relatively normal. Within the dermis there is a mild perivascular infiltrate of lym- phocytes and eosinophils

  

Figure 2.19 Arthropod Bite. A, Heavy inflammatory dermal infiltrate around necrotic focus. B, Section of the arthropod. (Courtesy of Dr Raffaele Gianotti, Milan, Italy.)

  

Figure 2.20 Acute Necrotizing Changes in Leukocytoclastic Vasculitis

 

Figure 2.21 Chronic Non-Necrotizing Vasculitis in Pigmented Purpuric Dermatosis

 

Figure 2.22 Perniosis is characterized by a superficial and deep peri- vascular lymphocytic vasculitis

 

Figure 2.23 Atrophie blanche is characterized by intravascular fibrin thrombi without a true vasculitis

 

Figure 2.24 Calciphylaxis. There is calcium deposition affecting vessels in the subcutis and associated fat necrosis

 

 

Figure 2.25 Urticaria Pigmentosa. A, Diffuse dermal infiltrate of mast cells admixed with eosinophils. B, High-power view of the infiltrate. (Courtesy of Dr Raffaele Gianotti, Milan, Italy.)

 

Figure 2.26 Urticaria Pigmentosa. Immunohistochemical demonstration of mast cells with tryptase

 

Figure 2.27 Sweet Syndrome. Diffuse dermal infiltrate of neutrophils with leukocytoclasis but without vasculitis

 

Figure 2.28 Cutaneous B-Lymphoid Hyperplasia. Dense infiltrate of reactive lymphocytes and histiocytes. Variable number of eosinophils or plasma cells may be present

 

Figure 2.29 Cutaneous B-Lymphoid Hyperplasia. Reactive germinal centers with frequent tingible body macrophages may be present

 

Figure 2.30 Clinical Appearance of Granuloma Faciale. The lesion appears as thickened purplish patches

 

 Figure 2.31 Vascular changes in granuloma faciale

 

Figure 2.32 A and B, Low- and Higher-Power Views of Cutaneous Sarcoidosis

 

Figure 2.33 Clinical Appearance of Multiple Lesions of Granuloma Annulare of Dorsum of Hand

 

Figure 2.34 Typical Lesion of Granuloma Annulare, With Palisading of Histiocytes Around "Necrobiotic Collagen" Center

 

Figure 2.35 Clinical Appearance of Lesions of Necrobiosis Lipoidica

 

Figure 2.36 Necrobiosis Lipoidica. Tiered arrangement of inflammatory cells and altered collagen

 

Figure 2.37 Necrobiosis lipoidica usually has lymphoplasmacytic aggregates

 

Figure 2.38 Scleroderma. Thickened collagen bundles with decreased spaces between the collagen bundles of the reticular dermis

 

Figure 2.39 Lichen Sclerosus

 

Figure 2.40 Erythema Nodosum. The inflammation predominantly affects the subcutaneous septae

 

Figure 2.41 Panniculitis With Scattered Multinucleated Giant Cells in Erythema Nodosum

 

Figure 2.42 Nodular Vasculitis/Erythema Induratum. The inflammation predominantly affects the subcutaneous lobule

  

Figure 2.43 Vasculitis in Nodular Vasculitis

  

Figure 2.44 Membranocystic Fat Necrosis of Lipodermatosclerosis

 

Figure 2.45 Clinical Lesions of Dermatitis Herpetiformis. Note the small size of the vesicles and their symmetric distribution

 

Figure 2.46 Clinical Appearance of Bullous Pemphigoid. Large bullae are present, some of which have ruptured

 

Figure 2.47 A, Bullous pemphigoid. A net separation is present between the epidermis and dermis, with protrusion of dermal papillae into the bulla. The inflammatory infiltrate is very scanty. B, Immunostaining for type IV collagen shows that the basement membrane is at the base of the bulla. (Courtesy Dr Fabio Facchetti, Brescia, Italy.)

 

Figure 2.48 Linear deposition of complement C3 in bullous pemphigoid

 

Figure 2.49 Clean subepidermal bulla of epidermolysis bullosa

 

Figure 2.50 Typical appearance of early lesion of dermatitis herpetiformis

 

Figure 2.51 Pemphigus Vulgaris. The bulla is in a suprabasal location

 

Figure 2.52 Pemphigus Erythematosus. The acantholytic cells are in a superficial location

 

Figure 2.53 Immunofluorescent Demonstration of Anti-Pemphigus Vulgaris Antibody 

Figure 2.54 Verruca Vulgaris. The lesion is cup-shaped and highly keratotic

 

Figure 2.55 Molluscum Contagiosum. A, Clinical appearance of lesion located in eyelid. B, Low-power view of cup-shaped lesion. C, High-power view showing numerous molluscum bodies. (A courtesy Dr Carlos Ramos, Belleville, Ilinois.)

 

Figure 2.56 A, Medium-power image of herpes simplex infection. B, High-power image of herpes simplex infection demonstrating large intranuclear inclusions

 

Figure 2.57 Hidradenitis Suppurativa. A heavy neutrophilic infiltrate is present around apocrine glands and in their dilated lumina. (Courtesy of Dr Raffaele Gianotti, Milano, Italy.)

 

Figure 2.58 Clinical Appearance of Lupus Vulgaris. The lesion presents in the form of an irregularly shaped red patch with elevated borders

 

Figure 2.59 Tuberculosis of Skin (Lupus Vulgaris). Well-formed granulomas with necrotic centers are present in the dermis

 

Figure 2.60 Lepromatous Leprosy. Large collections of foamy mac- rophages (Virchow cells) infiltrate the dermis

 

 Figure 2.61 Acid-fast stain shows leprosy organisms (arrows) in a perineurial inflammatory infiltrate. (Courtesy of Dr Raffaele Gianotti, Milan,

Italy.)

 

 Figure 2.62 Infiltration of the Arrectores Pilorum Muscle by Inflam- matory Cells. This is a diagnostic clue for the diagnosis of leprosy

 

 Figure 2.63 Palmar Lesions of Secondary Syphilis

 

 Figure 2.64 Secondary Syphilis. A, Low-power view showing a dense infiltrate predominantly affecting the upper dermis. B, High-power view showing markedly hyperplastic blood vessels surrounded by a lymphoplasmacytic infiltrate

 

 Figure 2.65 Numerous Treponema organisms are seen in this immunostain in a case of secondary syphilis. (Courtesy of Dr Fabio Facchetti, Brescia, Italy.)

 

 Figure 2.66 Lyme Disease. A perivascular infiltrate of lymphocytes and plasma cells is seen in the dermis

 

 Figure 2.67 Dermatophytosis due to Trichophyton, demonstrated by periodic acid-Schiff stain

 

 Figure 2.68 Clinical Appearance of North American Blastomycosis

 

 Figure 2.70 Blastomycosis. Budding yeast with thick refractile cell walls 

 Figure 2.71 Chromoblastomycosis. Pigmented septate organisms

 

 Figure 2.72 Pseudoxanthoma Elasticum

 

 Figure 2.73 Clinical Appearance of Darier Disease. The lesion typically affects the back and presents in the form of reticulated keratotic lesions

 

 Figure 2.74 Darier Disease 

 Figure 2.75 Eosinophilic Folliculitis in a Human Immunodeficiency Virus-Infected Patient