Oral verrucous hyperplasia: histologic classification, prognosis, and clinical implications.

Background: Oral verrucous hyperplasia (OVH) is a premalignant lesion that may transform into an oral cancer.

Methods: Sixty consecutive OVH cases were collected from 2003 to 2004. Clinicopathological features and the 5-year malignant transformation rate of these 60 OVH lesions were evaluated and analyzed.

Results: We found that 84% of OVH lesions occurred in patients between 40 and 69 years of age. The most common site for OVH lesions was the buccal mucosa (48%), followed by the tongue (20%), palate (18%), gingiva (7%), and labial mucosa (7%). Approximately 91% of OVH patients were areca quid chewers and 89% were smokers. When 60 OVH lesions were classified into 30 plaque-typed and 30 mass-typed OVH lesions, the mass-typed OVH lesions had a higher malignant transformation rate of 17% (5/30) than the plaque-typed OVH lesions (3%, 1/30) during a mean follow-up period of 59 +/- 7 months. The mean time for malignant transformation was 22 +/- 11 months. Of the 6 OVH lesions with malignant transformation, 2 underwent total surgical excision and 4 did not receive any form of therapy.

Conclusions: We conclude that OVH lesions occur more commonly on the buccal mucosa and are highly associated with the areca quid chewing and cigarette smoking habits. The overall 5-year malignant transformation rate of 60 OVH lesions was 10%. The mass-typed OVH lesions had a higher malignant transformation rate than the plaque-typed OVH lesions and thus should receive an immediate treatment, such as total surgical excision or photodynamic therapy, after the histopathologic diagnosis.