ILVEN-like persistent psoriasiform dermatitis confined to a congenital Becker nevus.

A 10-year-old boy presented with a 5-year history of an intractably pruritic, recalcitrant psoriasiform plaque in a broad vertical band on the left buttock, with histologic as well as clinical features suggestive of an inflammatory linear verrucous epidermal nevus. This lesion was completely superimposed upon a congenital Becker nevus. We postulate that the restricted distribution and persistence of the psoriasiform plaque reflected an inflammatory response limited to the aberrant clone of cells composing the Becker nevus, a manifestation of cutaneous mosaicism that could be characterized as an "inflammatory Becker nevus."