This 35 year old woman presented with a pigmented papule on her breast. Recent publications have identified a subset of breast nevi which are clinically unremarkable but have atypical histologic features, similar to those described at other anatomic sites (genital). Along with scalp, ear, and a growing list of others, these have been designated nevi of special sites. These are benign. The atypical features include lentiginous growth and cytologic atypica, to name a few, and these overlap histologically with nevi with architectural disorder. These have not been shown, to date, to be premalignant or be markers for malignancy, but are mere histologic observations not to be overdiagnosed as melanoma [J Cutan Pathol 2008;35:889-898].
The melanocytes are enlarged. They are present both singly and in nests, with lentiginous growth. Upward migration is not appreciated. The dermal component appears to mature.