Oral proliferative verrucous leukoplakia: Underdiagnosed oral precursor lesion that requires retrospective clinicopathological correlation.

We present herein a case of oral proliferative verrucous leukoplakia (OPVL) and discuss this relatively rare entity in light of current information. A 59-year-old woman, non-smoker, presented with a verrucous plaque at the left ventral and dorsal surfaces of the tongue that she had first noticed in 2001. At that time, the plaque was excised and revealed benign hyperkeratosis. The growth recurred and was again excised. Histologically it was characterized by a verrucous epithelial hyperplasia, hyperkeratosis and mild epithelial dysplasia. Human papillomavirus (HPV) DNA typing for low, intermediate, and high-risk groups was also performed and no etiological link between HPV and this lesion was found. The overall progressive clinical and histopathological findings were considered diagnostic for OPVL. Because of the lack of specific histological features and the progressive proliferative characteristic of OPVL, the recognition of this underdiagnosed entity is critical because apparently innocent looking oral verrucous lesions, irrespective of the presence of dysplasia, may progress into carcinoma. On the other hand, it is of interest that the early phase of these lesions usually exhibits an interface lymphocytic infiltrate that may mimic an oral lichenoid stomatitis such as lichen planus. It is therefore important to follow-up closely any patient with oral leukoplakia and those diagnosed with non-specific lichenoid stomatitis.