A Clinical Atlas of 101 Common Skin Diseases

Cysts and Cystic Hamartomas

Papules, nodules, and tumors that, on gross examination, are usually skin colored and, on histopathologic examination, consist of an epithelium-lined sac that contains fluid, cells, or both in the case of true cysts and of cysts that are associated…

Histologic Diagnosis of Inflammatory Skin Diseases

Applicable Terms

…llary dermis is responsible for the appearance clinically of a papule whose surface is flat, the prime example of that being the basic lesion of lichen planus. Not all diseases marked by flat-topped papules, however, exhibit bandlike infiltrates in t…

Histologic Diagnosis of Inflammatory Skin Diseases

Lichen planus

…, a blister in lichen planus does not form atop an established papule or plaque of the disease, and histopathologically, it is not associated with a lichenoid infiltrate of lymphocytes. Features typical of a papule of lichen planus are not seen benea…

Histologic Diagnosis of Inflammatory Skin Diseases

Selection of the Site

Because many inflammatory diseases of the skin, e.g., dermatitis herpetiformis, nummular dermatitis, scabies, Grover’s disease, and eosinophilic folliculitis, are exquisitely pruritic, scratching is an inevitable consequence, and signs of exco…

Histologic Diagnosis of Inflammatory Skin Diseases

Identification of Basic Patterns: Skin: Nodular and Diffuse Dermatitis

See Fig. 5.174 A&B. Figure 5.174 A&B. Nodular dermatitis and diffuse dermatitis. Nodular dermatitis is distinguished from perivascular dermatitis (see Fig. 5.16 A&B) by the density of the infiltrate of inflammatory cells. In the periv…

Histologic Diagnosis of Inflammatory Skin Diseases

Arthropod assaults

…following animated scratching of an insect “bite” Papules following on the “bite” of an insect may persist for months; vigorous rubbing of such papules may induce urtication anew Papular urticaria (lichen urticatus, strophulu…

Histologic Diagnosis of Inflammatory Skin Diseases

Identification of Basic Patterns: Skin: Perivascular Dermatitis

…ed in the interstitium should call to mind pruritic urticarial papules and plaques of pregnancy (PUPPP) (Fig. 5.27 A&B) on one hand and a drug eruption made up of macules and papules on the other (Fig. 5.28 A&B). Sometimes PUPPP is accompanie…

Histologic Diagnosis of Inflammatory Skin Diseases

Pyogenic granuloma

…ifest itself as macules/patches and nodules/tumors, as well as papules. A single papule of bacillary angiomatosis, hemangioma, and Kaposi’s sarcoma may be indistinguishable from one of pyogenic granuloma. Findings histopathologic Early Small…