Malignant transformation of proliferative verrucous leukoplakia to oral squamous cell carcinoma: a series of 55 cases.

In this study, we compared clinical differences between patients with proliferative verrucous leukoplakia (PVL) who did and did not develop oral cancer. This was a retrospective study of 55 PVL cases. All patients were followed for at least 1year, with a mean follow-up of 7.53 (SD=4.18) years. The mean age of the patients was 61.69 (SD=11.76) years. There were 36 (65.5%) females and 19 (34.5%) males. Group 1 included the 28 PVL patients who did not develop oral squamous cell carcinoma (OSCC) during the period. Group 2 included the 27 PVL patients who developed at least one OSCC during the period. The latter group was subdivided into patients with PVL who developed one (Subgroup 2a; n=16) or more than one (Subgroup 2b; n=11) OSCC during follow-up. There was no statistical difference in age or oral location of the PVL between Groups 1 and 2. Females had a greater tendency to develop cancer than males (58.3% vs. 31.6%). In Group 2, only six (22.2%) were smokers. There was no difference between Subgroups 2a and b in terms of age, gender, and oral location of the PVL. Subgroup 2b included fewer smokers, had higher gingival involvement rate, and lower frequency of PVL on the tongue. The PVL patients who develop oral cancers were more commonly female and non-smokers. Those patients who developed more than one OSCC were most likely to develop lesions of the gingiva.