PMC7780312_01
DM rash presenting as erythemato-violaceous papules and plaques on (a) the anterior chest area (V sign) and (b) dorsal finger's joints with periungual erythema.. DM: dermatomyositis.
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Erythemato-violaceous plaques with poikiloderma (atrophy, telangiectasias and dyspigmentation) were noted on peri-orbital regions, anterior chest, upper back, extensor surfaces of arms, lateral thighs and dorsal finger's joints (Figure 1).
Skin histology. (a) A hematoxylin phloxine saffron-stained section at 20x magnification showing rare necrotic keratinocytes with discrete vacuolization of the basal cell layer at the basement membrane zone and perivascular lymphocytic infiltrates and (b) staining with blue Alcian (pH 2.5) at 10x magnification highlighting increased dermal mucin deposition.
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Skin biopsy revealed rare necrotic keratinocytes with discrete vacuolization of the basal cell layer at the basement membrane zone, perivascular and periadnexial lymphocytic infiltrates and increased dermal interstitial mucin (Figure 2).
Muscle histology. (a) Hematoxylin and eosin section of semimembranosus muscle biopsy showing scattered purple staining necrotic and regenerative fibers without lymphocytic infiltration (200x magnification) and (b) immunohistochemical preparation for MHC-1 showing overexpression restricted to scattered necrotic fibers and lack of capillary dropout (100x magnification).. MHC: major histocompatibility complex.
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Quadriceps muscle biopsy showed scattered necrotic and regenerative fibers without inflammatory infiltrates or perifascicular atrophy (Figure 3).
Timeline of medical history and treatments.. IVIg: intravenous immunoglobulin; HCQ: hydroxychloroquine; MTX: methotrexate.
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A timeline of the history and treatments is presented in Figure 4.