Oral potentially malignant disorders. The significance of ‘hyperkeratosis’

Abstract

Introduction: Oral potentially malignant disorders (PMD) are a disparate group of mucosal disorders most frequently presenting as leukoplakia and characterised by their increased risk of squamous cell carcinoma (SCC) development. Contemporaneous management is based upon clinical assessment, incision biopsy microscopic grading of dysplasia severity and targeted intervention to treat high-risk lesions. It remains difficult, however, to accurately predict clinical outcome and many apparently innocuous lesions undergo malignant transformation. The aim of this investigation was to review the outcome for PMD lesions initially diagnosed as benign hyperkeratosis. Method: Review of anonymised clinical outcome data for a previously reported 590 PMD patient treatment cohort was carried out to identify cases in which initial incision biopsy diagnoses reported hyperkeratosis with no evidence of dysplasia. All patients underwent standardised assessment and treatment, including CO2 laser surgery and definitive histopathological assessment of excision biopsy specimens. Results: In total, 58 lesions (9.8%) were identified for review: 17 hyperkeratoses and 41 hyperkeratosis with lichenoid inflammatory features. Presenting primarily as leukoplakia at ventro-lateral tongue, floor of mouth and buccal mucosa sites, patients were more likely to be female (F:M Ratio 1.4:1) with a mean age of 60 years. Following excision, 10 hyperkeratoses (59%) required up-grading to more significant disease including 5 dysplasias (29%) and 2 SCC (12%), whilst 16 hyperkeratosis + lichenoid inflammation cases (39%) required revision identifying 13 dysplasias (32%) and 1 SCC (2%). Conclusions: Histopathological assessment of incision biopsy data is insufficient for definitive PMD diagnosis. A provisional diagnosis of hyperkeratosis does not exclude high-risk PMD. Clinician experience and judgement remain vital in comprehensive PMD assessment and management.