Histopathologic varieties of epidermal nevus.  A study of 160 cases. 
The histopathologic features of 167 biopsy specimens from 160 patients with clinically typical epidermal nevi seen at the Mayo clinic between 1960 and 1978 were reviewed.  The most common histopathologic pattern of epidermal nevus was hyperkeratosis, papillomatosis, and acanthosis with elongation of rete ridges.  Other histopathologic varieties of epidermal nevus included 1) acrokeratosis verruciformis-like, 2) epidermolytic hyperkeratosis, 3) seborrheic keratosis-like, 4)psoriasiform (inflammatory linear verrucous epidermal nevus), 5) verrucoid, 6) porokeratosis-like, 7) focal acantholytic dyskeratosis, and 8) nevus comedonicus.  Correlation of clinical and histopathologic findings is necessary in all lesions suspected of being epidermal nevus.