Combined nevi of the oral mucosa.

Pigmented nevi are uncommon oral lesions. We report the clinical and microscopic features of three cases of combined nevus, characterized by the association of an intramucosal nevus and a common blue nevus. Two cases were clinically suspected to be melanoma. The lesions were located on the maxillary gingiva, the mandibular gingiva, and the mucosa of the left posterior portion of the hard palate. Combined nevi of the skin vary considerably in histologic appearance. The microscopic findings demonstrated by oral combined nevi also appear to exhibit substantial histologic variation. The oral combined nevus should be differentiated from malignant melanoma by histopathologic means for, as in the skin, it appears to be clinically benign.