Successful topical sirolimus treatment of epidermal nevus in a patient with phacomatosis spilosebacea

Abstract

Epidermal nevi (EN) are hamartomas of keratinocytic or epidermal appendages which are most frequently seen as

isolated birthmarks. EN syndromes (ENS) are a heteroge- neous group of disorders caused by somatic mosaicism and

characterized by the presence of an EN with associated in- volvement of other organ systems.1

Phacomatosis spilose- bacea (PSS) is a rare ENS defined by the co-occurrence of

papular speckled lentiginous nevus (or nevus spilus) and nevus sebaceus (NS), a common type of EN.2

Postzygotic- activating HRAS mutation in a multipotent progenitor cell

has been described as the underlying pathogenetic mecha- nism of both types of nevi in PSS.2,3 Treatment of EN can

be challenging. Although full-thickness excision is curative, these lesions may occur in locations where the surgery would

result in disfigurement. Other treatments like topical corti- costeroids, retinoic acid and 5-fluorouracil or ablative laser

have been used with different and limited results.1,4