Purpose

This study of NFX-179 is an open-label study, evaluating safety, tolerability, pharmacodynamic activity, and the clinical effect in subjects with Epidermal Nevus(ENS). NFX-179 is formulated as a gel for topical administration. NFX-179 has been shown in animal studies and in human extracts to suppress p-ERK with systemic absorption of NFX-179 following topical application to be extremely low, based on serum values observed in animal studies. Primary objectives: * To determine the pharmacodynamic activity of NFX-179 Gel as defined by suppression of phospho-ERK (p-ERK) levels in Target EN in treatment group after 12 weeks of once-daily (QD) application * To determine the safety and tolerability of treatment with NFX-179 Gel 1.50% applied QD for 12 weeks. Secondary objectives: -Clinical effect of NFX-179 Gel 1.5% defined as the percent change in EN volume after 12 weeks of QD application