Differential diagnoses of solitary and multiple pigmented lesions of the oral mucosa: Evaluation of 905 specimens submitted to histopathological examination.

Background The aim was to analyze the frequency, clinical and demographic features of solitary and multiple/diffuse oral pigmented lesions submitted to histopathological examination, and to summarize the features that guide the clinical differential diagnosis. Methods Clinical and demographic data were retrieved from biopsy records and descriptive statistics were performed. Results Nine hundred and five (0.51%) oral pigmented lesions were retrieved among 177 356 specimens, being 95.9% solitary and 4.1% multiple/diffuse lesions. Regardless the overlapping clinical presentation, age, site, association with amalgam restoration, and a nodular appearance may help in the clinical differential diagnosis of solitary oral pigmentations. Patient's habits, site, and systemic signs and symptoms are helpful in the clinical differential diagnosis of multiple/diffuse lesions. Conclusions Oral pigmented lesions are a rare diagnosis in oral pathology and solitary lesions are more commonly submitted to biopsy. Some key features help in the differential diagnosis, though biopsy can be warranted in doubtful cases.