Pigmented oral lesions: Clues to identifying the potentially malignant

Oral nevi, melanotic macules on the lip, atypical amalgam tattoos, melanoacanthomas, and lesions caused by embedded foreign bodies or by perforating injuries of the oral mucosa all require biopsy, since they can resemble melanoma. An important clue in diagnosing melanoma is its marked tendency to ulcerate in the oral cavity. The amelanotic form may be mistaken for a pyogenic granuloma; thus, biopsy is essential. Lentigo maligna is a slow-growing, precancerous, pigmented lesion that generally occurs on the face; half of the reported cases in the oral cavity became malignant. Accordingly, complete excision is indicated. Take care not to confuse lentigo maligna with nevus of Ota, which involves the eye, facial skin, and oral cavity. Although it resembles lentigo maligna, it rarely becomes malignant. Other lesions that may be safely left alone are physiologic melanin deposits (usually gingival and buccal) in dark-skinned persons and oral pigmentation associated with pregnancy, Peutz-Jeghers syndrome, Recklinghausen's disease, HIV infection, and Laugier-Hunziker syndrome.