Eruptive Syringocystadenoma Papilliferum, Keratoacanthoma, and Verruca Vulgaris in a Keratinocytic Epidermal Nevus on the Leg.

An otherwise healthy 43-year-old man presented with seven papules that had all erupted within the previous 6 months from an epidermal nevus on his left lower extremity. He reported that one of the new growths was painful and bled with minor trauma. Physical examination revealed a linear blaschkoid cobblestoned dark brown plaque that extended from the disto-lateral left thigh 30 cm to the mid-calf. Within the plaque inferior to the lateral popliteal fossa were six verrucous papules and a 4-mm round, pink, crusted, exophytic papule (Figure 1). A punch biopsy was taken from the plaque and saucerization shave biopsies of all the discrete papules.