[Oral leukoedema--sequela of an artifact].

A 23-year-old white female with a history of psychological instability presented with burning, adhesive, white plaques of the buccal mucosa. She had been unsuccessfully treated for 1.5 years with topical retinoids as well as topical and systemic corticosteroids. The differential diagnoses included leukoplakia, cheek biting and lichen planus. Clinical and histopathological examinations suggested the diagnosis of severe oral leukoedema. Careful history and clandestine surveillance of the patient finally revealed the lesions to be due to a caustic (over-the-counter product for the treatment of corns), which the patient regularly applied to her buccal mucosa.