Histologic Diagnosis of Inflammatory Skin Diseases

Identification of Basic Patterns: Subcutaneous Fat: Panniculitis

See Fig. 5.385 A-C. Figure 5.385 Patterns of panniculitis. A. Septal mostly. B. Lobular mostly. C. Septal and lobular “equally.” At scanning magnification, the normal subcutaneous fat is seen to be segregated by struts of fibrous tiss…

Differential Diagnosis in Dermatopathology

Allergic (leukocytoclastic) vasculitis vs. Septic vasculitis

A small-vessel vasculitis characterized clinically by vesiculopustules on an erythematous base, purpuric macules and papules, and hemorrhagic bullae, and histopathologically by thrombi within venules, a consequence of sepsis….

Differential Diagnosis in Dermatopathology

Lymphomatoid papulosis vs. Mycosis fungoides, plaque

A small-vessel vasculitis characterized clinically by vesiculopustules on an erythematous base, purpuric macules and papules, and hemorrhagic bullae, and histopathologically by thrombi within venules, a consequence of sepsis….

Histologic Diagnosis of Inflammatory Skin Diseases

Atopic dermatitis

…per part of the epidermis; ragged base of the zone of necrosis Erosions, ulcers, and crusts Fibrosing granulation tissue in a thin zone immediately beneath an intact (re-epithelialized) epidermis or beneath an erosion/ulcer Correlation clinicopathol…

Histologic Diagnosis of Inflammatory Skin Diseases

Images

Images 10.23.1A: Perivascular dermatitis, psoriasiform + 10.23.1B: Orthokeratosis, hypergranulosis, acanthosis, proliferation of infundibular and eccrine ductal keratocytes, and coarse bundles of collagen in vertical streaks = Lichen simp…

Histologic Diagnosis of Inflammatory Skin Diseases

Lymphomatoid papulosis

Lymphomatoid papulosis Presentation stereotypical Age and sex More common in women who usually are more than 35 years of age, but children and other persons of both sexes are affected Distribution of lesions Widespread, usually on the trunk and prox…

Differential Diagnosis in Dermatopathology

Differential Diagnosis

Allergic (leukocytoclastic) vasculitis Septic vasculitis 1. Leukocytoclasis, i.e., nuclear “dust” of neutrophils invariable and abundant usually 1. No nuclear “dust” of neutrophils 2. Fibrin in and around the wall of ve…