case_images: PMC10224681_01
case_images: Clinical manifestation and histopathological findings of Porokeratosis Ptychotropica. (A) Clinical features show "butterfly shaped" verrucous plaque on buttocks with multiple satellite papules. (B) Dermoscopic view (X10) of the skin lesion, similar to keratotic ridge: annular, brown-yellowish hyperkeratotic ridge (arrows) demarcating a central area with whitish scales and some globular vessels. (C) A histological hallmark of all variants of porokeratosis, cornoid lamella (CL) as a "column" overlying a zone of the epidermis (cornoid lamella, marked as red asterisk). Dyskeratotic cells and focal hypogranulosis were present in the epidermis underlying the CL. Here, localized subcutaneous inflammatory cells infiltration suggested an eruptive pruritic PPt (H&E staining, X100).
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case_images: A 70-year-old Chinese woman presented with a 4-year history of progressive itching brown hyperkeratotic papules and plaques on her gluteal cleft and buttocks (Figure 1A). PPt in this case was made by an experienced dermatologist, and was confirmed by dermoscopy and histological findings of involved skin (Figure 1B and C). Previously, PK can be identified as a skin-specific auto-inflammatory disease, which was often inherited and linked to ultraviolet light exposure and immunosuppression.
case_images: Sanger sequencing chromatograms of proband (patient with PP, affected) and normal control (unaffected) at the c.64 G>A mutation site indicated by arrow (NM_000431: exon2:c.G64A:p.V22M).
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case_images: Sequence analysis showed a heterozygous C>A transition at nucleotide 64 in exon 2 of MVK in the patient (Figure 2), which was not detected in her brother and son or in 100 unrelated healthy controls. 