Definition: Two or more of the following patterns of melanocytic proliferation in a single lesion:

Ordinary nevus component*

Pigmented dendritic melanocytes*

Pigmented spindle/epithelioid cells

Amelanotic spindle cells

Spitz nevus cells

Clinical Definition: a melanocytic nevus surrounded by a hypo- or de-pigmented halo

Histologic Definition: a melanocytic nevus displaying a dense mononuclear cell infiltrate filling the papillary dermis

Concordance between clinical and histologic findings NOT 100%

Associated conditions: vitiligo (20%), malignant melanoma, atypical nevi