Potentially malignant disorder behaviour – Proliferative Verrucous Leukoplakia vs Lichenoid Inflammation

Abstract

Objectives: Clinically identifiable potentially malignant disorders (PMD) precede oral squamous cell carcinoma (OSCC). PMDs exhibiting Proliferative Verrucous Leukoplakia (PVL) or Lichenoid Inflammation (LI) are believed to exhibit treatment resistance & a higher risk of malignant transformation (MT). The objective of this study was to characterize & contrast clinico-pathological features in PVL & LI & to determine their influence on PMD behaviour. Methods: Retrospective review of 590 PMD patients treated in Northern England by CO2 laser between 1996 & 2014 with known clinical outcome. Lesions exhibiting PVL or LI were identified from a previously published database & the influence of clinico-pathological features on outcome analyzed. Results: 80 PVL & 118 LI cases were seen, predominantly leukoplakias on ventro-lateral tongue & floor of mouth, equally distributed between males & females. Most showed dysplasia on incision biopsy (85% PVL; 82% LI) & were treated by laser excision rather than ablation (86.25% PVL; 88.1% LI). LIs were more common in younger patients (PVL mean age 62.25yrs; LI mean age 57.1yrs; p=0.008) & more likely to present as erythroleukoplakia (PVL 2.5%; LI 15.3%; p=0.003). No significant clinical outcome differences were seen with 65% PVL & 69.5% LI disease free at study census (p=0.55), although less than overall PMD disease free status (74.2%)1. 2 PVLs (2.5%) & 2 LIs (1.7%) underwent MT. Conclusions: One-third of PMD cases exhibited PVL or LI with reduced disease free status, with LIs distinguishable as erythroleukoplakia in younger patients. MT is infrequent following interventional laser excision.