Pigmented lesions of the oral mucosa

The oral mucosa contains melanocytes, even though one might not suspect this when examining white subjects. Drug-induced pigmentation is usually irregularly distributed over the oral mucosa; typical causes are contraceptives and tetracyclines. Localized traumatic pigmentation can be due to injuries contaminated by foreign material (dust). Not infrequently an amalgam tattoo can be seen, caused by introduction of amalgam during dental treatment with rotating instruments. Focal melanosis is harmless. Neoplastic pigmentation is rare. Melanotic nevi are small with indistinct borders. Malignant melanoma occurs predominantly on the maxilla or hard palate. Frequently it has already metastasized by the time of diagnosis. Verification by biopsy is essential if a lesion has suddenly appeared, is extensive, elevated, with irregular pigmentation and has no obvious cause.