Porokeratosis palmaris et plantaris disseminata: broadening dermoscopic insights in a rare entity

Porokeratosis palmaris et plantaris disseminata (PPPD) is an exceptionally rare variant of porokeratosis characterized by abnormal clonal proliferation of keratinocytes along with distinctive histopathologic features-most notably, the cornoid lamella. It exhibits highly polymorphic clinical manifestations that pose significant diagnostic challenges. A 21-year-old man with PPPD presented with asymptomatic keratotic papules on the palms, soles, trunk, and limbs. Dermoscopy proved invaluable in guiding the diagnostic process, revealing annular structures interrupting the dermatoglyphics, with a brownish central clod and a whitish peripheral rim corresponding histologically to the cornoid lamella. The patient demonstrated significant improvement with oral acitretin and topical urea-based creams. This case illustrates the clinical nuances of PPPD, expands current dermoscopic insights into this rare entity, and underscores the critical role of dermoscopy in differentiating PPPD from other conditions in the differential diagnosis and in guiding biopsy procedures.