A 73-Year-Old Man With Eruptive Pruritic Brown Papules.

Eruptive disseminated porokeratosis (EDP) is a rare subtype of porokeratosis with the rapid onset of numerous pruritic papules and plaques on sun-exposed and sun-protected skin. We report a 73-year-old man with a one-year history of a progressively spreading pruritic eruption involving the lower extremities and forearms. Examination revealed brown verrucous papules coalescing into plaques. Histopathology demonstrated cornoid lamella, confirming porokeratosis. Paired exome sequencing identified a germline MVK variant with somatic loss of heterozygosity in affected skin, consistent with a second-hit mechanism in the mevalonate pathway. This case highlights the diagnostic challenges of EDP and underscores the importance of clinicopathologic correlation.