A 53-year-old man presented with asymptomatic, ulcerative, whitish plaques on the buccal mucosa and tongue. The buccal mucosa and tongue lesions had developed 1 year and 2 months ago, respectively. Physical examination revealed two, 0.8 cm, ulcerative, whitish plaques on the upper buccal mucosa and ventral portion of the tongue. No cervical lymphadenopathy was found. He had no remarkable medical or family history. The patient was initially treated with prednisolone 10 mg for 2 weeks. The lesions showed partial response to prednisolone but relapsed a few months later. Thus, a skin biopsy was performed at both sites.