The malignant progression of oral leukoplakia has been sometimes reported.
In this report, a man with leukoplakia on his buccal mucosa, which was treated with, cryotherapy but later showed a transformed squamous cell carcioma on the same region, was presented. A 55-year-old man visited our clinic with an extended white lesion on his right buccal mucosa. From the biopsied specimen this lesion was diagnosed as leukoplakia. At first cryotherpy was given but a small lesion remained. Nine years after therapy, an oral squamous cell carcinoma was proven from the biopsy of this lesion. Cryotherapy was inure frequently used from 1970 to 1980s.
This case suggested that cryotherapy for oral leukoplakia must be applied more carefully, especially when the lesion is large, and needs a long term follow up.
