The term dermal nevus encompasses two clinical, dermoscopic and histopathologic rather distinctive variants of benign melanocytic nevi, namely, Unna nevus (papillomatous dermal nevus) and Miescher nevus (dermal nevus of the face).
Clinically, Unna nevus is a soft polypoid or sessile, usually papillomatous lesion frequently located on the trunk, arms, and neck. The clinical features of Miescher nevus are rather firm, brownish to nearly skin-colored, dome-shaped papules that occur mostly on the face [Unna 1885, Miescher 1956, Magana-Garcia and Ackerman 1990].
Dermoscopically, Unna nevi reveal a globular pattern composed of numerous light- to dark-brown, round to oval globules distributed regularly throughout the lesion, or a cobblestone pattern consisting of larger, somewhat angulated globular structures. In addition, Unna nevi in some instances display densely packed exophytic papillary structures, which are commonly separated by irregular, black comedo-like openings also known as irregular crypts. These exophytic papillary structures correspond to an exaggeration of the papillomatous surface of an Unna nevus.