This is a retrospective study from Sweden where 234 patients, diagnosed between 2003 and 2013 with a median nine-year follow-up, were reviewed. Of these 234 patients, 11.5% developed oral squamous cell carcinoma. Non-homogenous leukoplakia showed a 15-times higher transformation rate than homogenous. Dysplastic leukoplakias developed carcinomas in 2.4 times more often than non-dysplastic leukoplakias. Leukoplakia located to the tongue showed a nearly three-times higher malignant transformation than other oral leukoplakias. They noted that the number of lesions, gender, age, or smoking habits, did not affect the malignant transformation rate. The authors acknowledge the problems with subjective grading of dysplasia and that the pathological specimens had not been re-evaluated from their original grading. The transformation rate appears a little higher than the often quoted 2-4% but is in line with other papers, suggesting that this is due to the long follow-up period and an estimation of a yearly transformation rate of approximately 1%.