case_images: PMC11313490_01
case_images: Clinical images showing polymorphic erythematous to-brown round lesions on the body of the patient.
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case_images: A 69-year-old Chinese male had a 50-year history of progressively spreading papules, which initially appeared on his upper limbs and later spread to involve his lower limbs, face, chest, and back bilaterally (Figure 1).
case_images: (A) Dermoscopy of the lesion corroborated the clinical features showing some brown circular and branched structures on an erythematous background. (B) Skin biopsy of the abdomen reveals some cornoid lamellae and intense hyperkeratosis, a perivascular lymphocytic inflammatory infiltration in papillary dermis (hematoxylin and eosin [H&E] stain). (C) A column of parakeratotic cells is seen correlating to the raised border of the lesion (hematoxylin and eosin [H&E] stain). The presence of the cornoid lamella, indicated by the black arrow, serves as a distinctive histopathological marker for all subtypes of porokeratosis.
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case_images: Dermoscopic evaluation of a representative lesion revealed brown circular and dendritic structures superimposed on an erythematous background (Figure 2A), that could suggest a form of PK. Furthermore, a band-like lymphocytic infiltrate was observed at the dermo-epidermal junction (Figure 2B). Additionally, a column of parakeratotic cells was detected, which seemed to align with the raised perimeter of the lesion (Figure 2C).
case_images: Sanger sequencing chromatograms of proband (patient with DSP, affected) and normal control (unaffected) at the c.746T>C mutation site indicated by arrow [NM_002461.3: exon7: c. T746C: p.F249S].
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case_images: Traditional Chinese Medicine and conducted according to the Declaration of Helsinki principles. To further investigate the genetic basis of this condition, Sanger sequencing was performed on DNA extracted from EDTA blood (Figure 3).