Blaschkolinear congenital melanocytic nevus.

common acquired nevi and an otherwise normal clinical examination. Congenital melanocytic nevi are often classified according to their size [1] . Another attempt of classification in two groups has recently been proposed: type I, the most frequent, with a single lesion involving one anatomic area and type II, less common, with a larger lesion and dozens of smaller ones, with a similar pattern on histological analyses, involving more than one anatomic area [2] . The lines of Blaschko were described in 1901 by Alfred Blaschko [3] . They are thought to follow the dorsum-to-ventral migration of the epidermal cell clones from the neural crest to the genetically programmed definitive skin location [4] . Several observations of common monogenic or polygenic skin disorders following Blaschko’s lines have been reported [4, 5] . Linear congenital melanocytic nevus as seen in our case has been reported once [5] . Focusing on large congenital melanocytic nevi, Effendy and Happle [6] reported in 1992 the first case of congenital melanocytic nevus, constituted of an association of multiple nevi with linear arrangement involving an arm, following the lines of Blaschko. This case and the present patient could be defined as having type II congenital melanocytic nevi [2] . More recently, a study has analyzed 92 cases of congenital melanocytic nevi and has claimed that 39 could be considered to match the lines of