Pigmented lesions of the oral mucosa: A cross-sectional study of 458 histopathological specimens.

OBJECTIVES: To evaluate clinical, demographic, and histopathological characteristics of pigmented lesions of the oral mucosa.

MATERIALS AND METHODS: A cross-sectional study was conducted over a 64-year period. Information was collected from medical charts, and all archived histopathological specimens with diagnoses of any pigmented lesion were retrieved. Statistical analysis was performed using SPSS software.

RESULTS: A total of 34,127 archived specimens were reviewed, revealing 458 (1.34%) pigmented lesions, of which 230 were melanocytic and 228 nonmelanocytic. Most patients were females (74.2%), white-skinned (49.1%), in the third and seventh decades of life (mean of 45 years). Most lesions were macular (59.8%), followed by plaques and nodules (4.8%), measuring 0-5 mm (41.9%). Cheek mucosa (21.0%), alveolar mucosa (16.6%), and gingiva (11.8%) were the most commonly affected sites. Amalgam tattoo was applied in 212 cases (46.3%), followed by melanotic macule (22.9%) and nevus (20.5%). Other diagnoses included racial pigmentation, exogenous pigmentation, melanotic neuroectodermal tumor of infancy, melanoma, melanoacanthoma, smoker's melanosis, and heavy metal pigmentation.

CONCLUSIONS: Pigmented lesions represent an uncommon diagnosis in oral pathology routines. The most frequent entities are amalgam tattoo, melanotic macule, and nevus. Patients are usually middle-aged women presenting a small, long-lasting, macular lesion on the cheek mucosa.