Adult Progression of Congenital Inflammatory Linear Verrucous Epidermal Nevus with Bilateral Acral Involvement

Abstract Inflammatory linear verrucous epidermal nevus (ILVEN) is a rare variant of epidermal nevus, typically presenting during infancy or early childhood, and is characterized by unilateral, erythematous, hyperkeratotic, and verrucous plaques that follow the Blaschko lines. ILVEN is classically pruritic, with lesions that are often refractory to standard treatments. We report a 38-year-old woman with congenital, asymptomatic ILVEN confined to the leg. After decades of quiescence, rapid adult progression with bilateral hand lesions occurred. Histology revealed psoriasiform epidermal hyperplasia with alternating vertical tiers of parakeratosis and orthokeratosis. The parakeratotic zones were overlaid by areas of diminished or absent granular layer (hypogranulosis), while the orthokeratotic zones demonstrated retained hypergranulosis. Findings were consistent with ILVEN. Given the widespread lesions and absence of disabling symptoms, conservative management with acitretin was initiated. This case illustrates the clinical variability and mosaic inflammatory nature of ILVEN, highlighting atypical features such as adult onset, bilateral acral distribution, and lack of systemic manifestations. This unusual course expands ILVEN spectrum and supports molecular evaluation in atypical cases. Future studies on the genetic basis of ILVEN may guide targeted therapies and improve management of extensive or refractory cases.