A 73-Year-Old Man With Eruptive Pruritic Brown Papules.
Xingyuan Jiang, Angela J Luo, Ana Preda-Namescu et al.
✦ AI-curated · Sources linked
Case in brief
A 73-year-old man presented with a year-long, progressively spreading pruritic eruption on his lower extremities and forearms. Examination showed brown verrucous papules merging into plaques. Biopsy demonstrated cornoid lamella, supporting a diagnosis of porokeratosis. Paired exome sequencing found a germline MVK variant and somatic loss of heterozygosity in affected skin, consistent with a second-hit mechanism involving the mevalonate pathway.
What made this case unusual
Sequencing linked the skin findings to a germline MVK variant with somatic loss of heterozygosity in affected tissue, consistent with a second-hit mechanism.
Diagnostic / clinical pearl
Cornoid lamella on histopathology can confirm porokeratosis in a patient with a spreading pruritic papular eruption; diagnosis benefits from clinicopathologic correlation.