White, red, and mixed lesions of oral mucosa: A clinicopathologic approach to diagnosis

A wide range of conditions could present as persistent white or red, or mixed white and red patches on the oral mucosa. Discussed here are some common conditions encountered in clinical practice that appear as white or red patches, together with some rare, but clinically significant, conditions. Based on pathognomonic features, major diagnostic criteria are outlined to help with the differential diagnosis, while some require further investigation (eg, biopsy and/or microbiologic or hematologic investigation) to confirm the provisional clinical diagnosis. Two conditions that require special consideration are leukoplakia and erythroplakia, as they have the potential to transform to cancer.