Oral linear epidermal nevus: a review of the literature and report of two new cases.

Linear epidermal nevus (LEN) is a sporadic hamartomatous lesion of the skin due to the proliferation of clones of embryonic ectodermal cells, which are arranged according to a typical linear configuration known as Blaschko's lines. Oral involvement of LEN is very rare and few cases have been reported in the medical literature. We report two new cases of LEN with exclusive oral involvement, which presented with the typical unilateral or midline distribution.