Pigmented nevi of the oral mucosa: a clinicopathologic study of 36 new cases and review of 155 cases from the literature. Part II: Analysis of 191 cases.

Review and analysis of data on 191 cases of oral pigmented nevi from the literature and from two studies at the University of California, San Francisco, revealed that nevi of the intramucosal type are the most common, followed by the common blue nevus. Compound and junctional nevi are rare, and combined nevi are the rarest. The data on location, presence of clinical pigmentation, configuration, size, and duration of the nevi, as well as on the patient's age, sex, and race, are analyzed. Blue nevi were found mostly on the hard palate, whereas intramucosal nevi occurred on the buccal mucosa, on the gingiva, and on the lips as well as on the palate. Nonpigmented nevi were especially common (22%) in the intramucosal group. Most oral nevi are raised, which can be of help in the differential diagnosis. Oral nevi are small, most being between 0.1 and 0.6 cm at the largest dimension. Because the malignant potential of oral nevi is still uncertain and because preexisting macular pigmentation is present in about one third of all patients with oral melanoma, it is advisable to accurately diagnose all oral pigmented lesions, many of which will require microscopic examination.