Non-Neoplastic Dermatopathology

5.8

C OLD PANNICULITIS VS LUPUS PANNICULITIS

Cold Panniculitis

Lupus Panniculitis

Age

Any age, including infants, children, and adults.

Variable age of presentation but typically between 30 and 60 years of age. More frequent in women. Most commonly involves upper arms and shoulders but can involve trunk, buttocks, chest, face, and scalp. Autoimmune disorder caused by failure of the mechanisms that maintain self-tolerance. Genetic and environmental factors, including ultraviolet radiation, sex hormones, and medications, contribute to the pathogenesis. Autoantibodies, directed toward a variety of nuclear proteins, mediate tissue injury. Tender, deep-seated, indurated, erythematous nodules or plaques. Lesions may be solitary or arise in crops involving multiple regions. 1. Variable superficial changes of hyperkeratosis, interface vacuolar degeneration, perivascular lymphocytic infiltrate, and dermal mucin deposition. In many cases, the epidermis and dermis are unremarkable. 2. Predominantly lobular infiltrate of small lymphocytes without cytologic atypia (Figs. 5.8.6 and 5.8.7) . May have associated germinal center formation and plasma cells. 3. Lymphocytic vasculopathy with infiltration of subcutaneous vessel walls by lymphocytes, endothelial swelling, and erythrocyte extravasation (Fig. 5.8.8) . 4. Hyaline sclerosis and myxoid change of collagen of deep dermis and subcutaneous septa (Figs. 5.8.9 and 5.8.10) .

Location

Typically on thighs, buttocks, lower abdomen in adults. Cheek and forehead involved primarily in infants. Exposure to prolonged cold leads to vascular damage and crystallization of the subcutaneous fat resulting in inflammation in the area. Erythematous or violaceous, indurated, ill-defined nodules. May have ulceration. Pruritus and burning variably present. Lesions typically evolve 24-48 hours after cold exposure. Associated with horse riding in women, ice pack use, and eating cold items in young children. 1. Superficial and deep perivascular lymphocytic infiltrate in the dermis (Figs. 5.8.1 and 5.8.3) . 2. Lymphocytic lobular infiltrate within the subcutis with lipophagic features (Fig. 5.8.4) . 3. Perieccrine and perineural lymphocytic inflammation (Fig. 5.8.2) . 4. Lymphocytic vasculopathy may be evident. 5. Mucin deposition (Fig. 5.8.5) may be present as in lupus erythematosus; therefore, clinical correlation is necessary.

Etiology

Presentation

Histology

5. Lipomembranous fat necrosis involving subcutaneous fat lobules occasionally seen. Copyright © Wolters Kluwer, Inc. Unauthorized reproduction of the content is prohibited. 2023

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