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.