MELANOPLAKIA—a brown-black oral mucosal pigmentation—is literally a "black plate," and by definition the pigment need not be melanin. It has been described under various terms but most probably is a lentigo. Although opinions differ, the red free margins of the lips are herein considered as mucous—rather than cutaneous—surfaces. Melanoplakia is physiologic in Negroes, frequent in yellow and brown races, and relatively frequent in white persons with "dark" complexion. It also has been associated with (1) local factors—including heavy metals, foods, dental abnormalities, foreign bodies, dyes, acids, gases, and drugs; (2) radiant energy, especially in the ultraviolet range; (3) malignant growths, including Hutchinson's lentigo maligna—7% of malignant melanomas arise from an initial lesion in the oral mucosa; (4) systemic diseases—including Addison's disease, cachexia, carcinomatosis, diabetes, hemochromatosis, hyperthyroidism, tuberculosis, malaria, Niemann-Pick disease, hepatic diseases, pancreatic diseases, gynecologic diseases, and rarely pernicious anemia, pellagra, sprue, and Gaucher's disease, and (5)