AIM To compare cyclooxygenase 2 expression (COX2-E) between normal, oral leukoplakia lesions and different grades of oral squamous cell carcinoma (SCC). MATERIALS AND METHODS Around 90 paraffin embedded blocks consisting of 45 SCC, 15 leukoplakia and 17 controls were selected for immunohistochemistry (IHC) for detection of COX2- E. COX2-E was divided in four grades, as A (0-10%), B (11- 40%),...

Proliferative verrucous leukoplakia (PVL) is a particularly aggressive form of oral leukoplakia that is resistant to treatment and presents a high risk of recurrence and malignant transformation. This article describes the microscopic and clinical characteristics of one case of PVL, which initially presented as hyperkeratosis with mild dysplasia and posteriorly developed multifocal areas and ve...