Sebaceous Nevus
摘要
Sebaceous nevus (SN) is a congenital hamartoma occurring on the scalp or face. At birth, SN presents as a congenital hairless area with a smooth, flesh-colored surface with a pink or orange cast. At puberty, it develops a velvety and verrucous surface. In early stage of SN, dermatoscopy shows bright-yellow dots not associated with the hair follicles, as well as the “hen feet sign,” characterized by the presence of linear yellow structures, grouped in clusters of 2–3 elements often with a common base of origin. In middle phases, SN shows a global pattern ranging from cobblestone, cerebriform, papillomatous, and lobular. On a pink-orange and/or yellow-white to brown background, it is possible to identify round to oval yellowish/orange structures of different sizes, resembling dots or globules, sometimes gathered in clusters and/or associated with a whitish network. In the late stage, dermatoscopy of SN shows fissures and ridges arranged in a cerebriform pattern and/or verrucous proliferations.