Idiopathic leukoplakia lingualis.

A 67-year-old man had a nonspecific leukoplakia of the tongue. It was of recent onset and had no readily apparent etiology. From the differential diagnosis of seven conditions, biopsy was consistent with a benign hyperkeratotic process. Although several atypical cells were noted in the epithelium, no foci of dysplasia or frank squamous cell carcinoma were observed. The characteristic histologic features of lichen planus, hairy leukoplakia, and hyperplastic candidiasis were similarly not present in the biopsy specimen. No evidence of coexisting systemic disturbances or risk factors associated with lupus erythematosus or human immunodeficiency virus infection were evident from the workup. The lesion's recent onset was inconsistent with white sponge nevus. This oral lesion can be best described clinically as an idiopathic leukoplakia. Histologically, it displayed hyperkeratosis of the epithelium. When oral leukoplakia of unknown etiology is encountered, careful consideration of contributing history, oral habits, systemic diseases, and histologic findings is necessary to achieve an accurate diagnosis. Developing a differential diagnosis can aid in systemically ruling out various entities as clinical and laboratory data are obtained.