Case report
A seven-year-old girl presented with hyperkeratotic verrucous papules in a blaschkolinear distribution on the sole of her left foot. The lesions were congenital and asymptomatic. She had a family history of atopic dermatitis but no significant past medical history. Prior to presentation, the lesions were treated with topical antifungals and salicylic acid, with no conferred benefit. On examination there were unilateral hyperkeratotic papules coalescing into plaques in a linear configuration following lines of Blashko on the lateral border of the left sole (Figure 1).
Histopathological analysis showed columns of parakeratosis associated with scant dyskeratotic keratinocytes in the upper granular layer reminiscent of cornoid lamellae (Figure 2). A deep infiltrate involving sweat ducts was absent.