Clinicopathological Discordance of Biopsy Findings in Proliferative Verrucous Leukoplakia: Series of 5 Cases

Background: Proliferative verrucous leukoplakia (PVL) is a rare but aggressive variant of oral leukoplakia. Lesions within the spectrum of PVL are characterised by high recurrence rates and high risk of malignant progression. Their multifocal and metachronous occurrence in patients necessitates close follow-up with combined clinical and histopathological examination by sampling biopsies. However, their clinical reliability is limited due to the elusive clinical presentation of PVL, as histological features can differ within a single lesion. To date, there are no studies that have investigated the diagnostic accuracy of biopsies of PVL-associated lesions. Case Presentation: Out of a total of 33 reviewed patients from retrieved records, five cases with discordant biopsies were identified and were analysed in more detail based on available photographic documentation and histopathological findings. The presentation seeks to illustrate the resulting diagnostic and therapeutic challenges of inconclusive biopsies in PVL. Discussion: In the five cases presented, divergent interpretations of biopsies appeared to be related mainly to inconclusive or superficial biopsy sampling. An incidental finding in one case was a rare occurrence of leukoplakia on a pedicled myofascial graft with subsequent malignant transformation. Conclusions: Due to the characteristics of PVL-associated lesions, it is likely that the discordance rates are higher than for other oral potentially malignant disorders (OPMD). When repeated biopsies remain negative despite a strong clinical suspicion of malignancy, a full-thickness biopsy including submucosal tissue or complete excision of the lesion should be considered within an interdisciplinary setting.