Hypopigmented Papules in Infancy: A Diagnostic Challenge: Answer

Abstract

Papular epidermal nevus with "skyline" basal cell layer (PENS). COMMENTEpidermal nevi are benign overgrowths of epidermal keratinocytes. They typically present at birth or in infancy as a linear hyperpigmented patch or plaque, following lines of Blaschko. With time, lesions may become thicker and more verrucous. 1 Although most epidermal nevi are isolated to the skin, rare cases of extensive epidermal nevi may be associated with abnormalities of the eyes, skeletal, cardiovascular, urogenital, or central nervous system. 1 PENS is a rare subtype of epidermal nevi. Interestingly, 50% of reported cases of PENS have been associated with neurological abnormalities in childhood. 2 The syndrome was first described by Caputo and Tadini in 2006, and in 2011, the term PENS was coined. 3,4 PENS most commonly presents as asymptomatic, small, round or polygonal hyperkeratotic papules or plaques. The color of lesions can range from white to brown, [4][5][6]10,13 and in some cases, lesions of different color may be present in the same individual. 7,10,11 Unlike epidermal nevi that occur linearly along lines of Blaschko, 4 PENS lesions do not typically follow a similar distribution and mostly occur in a sporadic distribution, with a predilection for the face, neck, trunk, and extremities, while sparing the palms and soles. 4 Only 2 PENS cases have been described following a Blaschkoid distribution. 6,7 To date, 22 cases of PENS have been reported in the literature. In 15 cases, lesions were present at birth, with a From the