Although most scalp nevi can be readily classified into the regular nevus subtypes- common, congenital, blue etc, exceptionally they may show features more commonly seen at “the socalled milk-line” sites. Some authors use the term “atypical nevus of the scalp”.

Histological features

•Junctional/compound

•Large dyscohesive nests with retraction artifact, not restricted to the tips of the epidermal ridges

•Heavy pigmentation (sometimes gray/green)

•Bridging common, often over multiple rete ridges

•Variable atypia (can be marked)

•Central pagetoid spread

•Superficial dermal atypia

•Junctional mitoses sometimes present, dermal mitoses+/-, can be multiple but never atypical

•Dermal fibrosis (sometimes lamellar)

. HMB45 shows gradation with depth, Ki67 is low