Objective: To present a clinical, histopathological and ultrastructural study on a group of patients affected by idiopathic mucocutaneous pigmentation (Laugier-Hunziker syndrome: LHS).
Materials and methods: Twelve patients were investigated: clinical examination, laboratory tests, and X-ray studies together with light microscopy and electron microscopy were performed in order to diagnose LHS.
Results: All cases showed acquired, benign, macular hyperpigmentation of buccal mucosa lips and nails. Histologically, pigmentations are due to an accumulation of melanin in the basal layer keratinocytes and an increase in the number of melanophages in the submucosa and/or papillary dermis. Ultrastructurally there were increased numbers of normal-appearing melanosomes in keratinocytes of the lower epithelium. No evidence of malignant changes were detected.
Conclusions: The importance of this condition relates to it being included in the differential diagnoses of pigmentary disorders of the oral mucosa with associated nail involvement. It is important to recognize this acquired benign disorder to avoid unnecessary investigations and treatments.