PMC9910515_01
PMC9910515_02
(a): Umblicated papules with central keratin plug. (b): Koebner's phenomenon
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Majority of our patients had multiple, umblicated papules with central keratin plug, some are distributed in linear and annular patterns [Figure 1a, 1b].
(a&b): Multiple, giant, crusted plaques of varying sizes all over the abdomen and trunk
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Patient 7 had multiple, giant, crusted plaques of varying sizes all over the abdomen, trunk, chest, thighs, and limbs [Figure 2a, 2b].
(a&b): Umblicated papules with central keratin plug with psoriatic lesions on lower limbs
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Patient 8 had typical ARPC lesions adjacent to psoriatic lesions on the lower limbs [Figure 3a, 3b].
(a): Cup-shaped epidermal depression with a central crater containing neutrophils, basophilic debri, parakeratotic horny material and degenerated collagen in vertical strands (H&E x50). (b): High-power view highlighting the degenerating collagen bundles, vertically oriented, and the basophilic debris within the crater (H&E x200)
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The histopathological features of skin lesions in all 15 patients were consistent with ARPC: cup-shaped epidermal depression with a central crater extending from epidermis to the dermis and containing neutrophils, basophilic debri, parakeratotic horny material, and degenerated collagen in vertical strands [Figure 4a, 4b].
Masson's trichome stain revealing vertically oriented collagen bundles (400x)
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Masons trichome stain revealed vertically oriented collagen bundles [Figure 5] and Van Gieson stain failed to stain elastin fibers.