Laugier and Hunziker pigmentation: a lentiginous proliferation of melanocytes.

Macular pigmentation of Laugier and Hunziker is an acquired disorder involving lips, oral mucosa, acral surfaces, nail apparatus, or a combination of these in the absence of systemic disease, and is reported to show intraepidermal melanosis without melanocytosis. We present a 69-year-old white man with typical features of this disorder, involving lips and oral mucosa, first appearing 4 years before presentation. A pigmented macule on sun-exposed lip vermilion revealed increased numbers of slightly atypical melanocytes in a lentiginous epidermal pattern. A buccal mucosa pigmented macule and adjacent nonpigmented mucosa were studied using hematoxylin and eosin staining, and S-100 and L-3,4 dihydroxyphenylalanine histochemistry. The buccal mucosa macule revealed markedly increased numbers of dendritic, L-3,4 dihydroxyphenylalanine-reactive intraepithelial melanocytes. Further studies are warranted to determine if this pigmentation disorder represents a spectrum of histopathologic change or, in fact, should be renamed mucocutaneous lentiginosis of Laugier and Hunziker.