Exophytic oral verrucous hyperplasia: a new entity.

Abstract

Exophytic oral verrucous hyperplasia (OVH) is a new entity described by an expert working group from South Asia. First reported in Taiwan, there are no reports so far from an Indian population. The aim was to use the microscopic features described by the expert group to differentiate OVH from other oral verruco-papillary lesions in an Indian archive. In a retrospective multicentre study, using pathology archives, 188 verruco-papillary lesions were retrieved from pathology archives. A proforma listing histopathological criteria for OVH based on published guidelines (Annals of Dentistry, University of Malaya, 2013) was used. Patients' demographic and clinical data were transcribed from patient charts. The Pearson chi-square test was used to determine associations between clinical and histopathological features. Of 188 oral verruco-papillary lesions that were evaluated, based on microscopic features the cases were reclassified as OVH (57), verrucous carcinoma (VC) (84), oral squamous cell carcinoma (16), and other verruco-papillary lesions (31). Both OVH (70%) and VC (60%) showed male predominance and commonly affected buccal mucosa (OVH 74% and VC 57%). Absence of downward growth of the hyperplastic epithelium into lamina propria when compared with the level of the basement membrane of the adjacent normal epithelium was a distinct feature in OVH. Keratin plugging, epithelial dysplasia and subepithelial lymphocytic infiltration were found to be significantly different (P<0.05) in OVH versus VC. The sample size of other verruco-papillary lesions was insufficient for statistical comparison. Apart from the absence of an endophytic growth pattern in OVH, we noted the presence of dysplasia in OVH. This significant observation does institute a debate as to whether this enigmatic lesion could possibly be a precedent of oral squamous or verrucous carcinoma. We propose OVH is a distinct entity in our Indian population and should be considered in the classification of oral potentially malignant disorders.