case_images: PMC11745285_01
case_images: Clinical findings. Clinical pictures showed reddish papules and nodules scattered from the left lower abdomen to the dorsal aspect of the hip, with a zonal arrangement (A-C). Note that there were no eruptions from the center to the contralateral skin. A close-up view of the skin lesions illustrated non-fused, reddish papulo-nodules with center plugs in each (D), consisting with dermoscopic finding (E).
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case_images: Th12-L3 (Fig. 1A-C). The eruptions had well-demarcated central plugs, consistent with dermoscopic findings (Fig. 1D-E). Tzanck smear test underneath the plugs was negative, and repeated microscopic examination of the crusts was negative for scabies.
case_images: Histological and immunohistological findings. Skin biopsy pathology showed a central erosion filled with a cup-shaped keratinous plug containing numerous inflammatory cells and collagen fibers, and perivascular infiltrates consisting of lymphocytes and eosinophils in the dermis (A, Hematoxylin & eosin, x40; B, Hematoxylin & eosin, x200). Elastica van Gieson staining visualized vertically trans-eliminated collagen fibers from the underlying dermis through the plug (C, x200). Immunostaining using anti-pankeratin AE1/AE3 antibody revealed no periappendage materials within the plug (D, x40).
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case_images: Skin light microscopy showed a central erosion filled with a cup-shaped plug containing keratinous debris, collagen fibers, and numerous inflammatory cells mainly consisting of lymphocytes and eosinophils in the dermis (Fig. 2A-B). Vertically oriented collagen fibers, visualized by Elastica van Gieson staining, were extruded from the underlying dermis through the plug (Fig. 2C). There were no skin appendage materials within the plug, estimated by immunostaining using antibodies to pankeratin AE1/AE3 (Fig. 2D).
case_images: Clinical findings after treatment. After 6 months of oral dapsone treatment, all the eruptions flattened and almost disappeared with mild pigmentation (A, B).
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case_images: After 6 weeks, the eruptions flattened and almost disappeared with mild pigmentation (Fig. 3A-B), and did not recur thereafter.