Abstract
It remains controversial whether oral lichen planus become malignant. We report four cases (three males and one female, average age, 65.5 years) of squamous cell carcinoma suspected to be derived from an oral lichen planus. The site involved were the buccal mucosa, upper gingiva, lower gingiva and tongue, respectively. All showed an erosive appearance macroscopically, and were diagnosed as lichen planus in three cases ; in the remaining case, carcinoma and lichen planus appeared simultaneously. The intervals between the patients' first visits and recognition of squamous cell carcinoma were 33, 49, and 106 months, respectively. One of the patient was smoker and two were drinkers. One patient is now alive and free from tumor, while the remaining patients have died.
