Coexisting oral potentially malignant disorders as a candidate risk factor for malignant transformation: a case report and proposal for a modified leukoplakia decision tree

Abstract

Oral potentially malignant disorders (OPMDs), including leukoplakia and oral lichen planus, carry an increased risk of malignant transformation to oral squamous cell carcinoma, with reported rates of 6.64–9.5% for leukoplakia and 0.7–1.4% for lichen planus. Current decision trees recommend excision whenever feasible and do not stratify non-dysplastic lesions by risk factors, nor do they address whether the coexistence of multiple OPMDs should itself lower the threshold for intervention. This report describes the case of a 73-year-old man with pre-existing oral lichen planus who developed a new, non-dysplastic leukoplakic plaque on the lateral border of the tongue. Despite the absence of dysplasia on initial biopsy, the lesion was excised in light of the lesion’s high-risk features and the patient’s coexisting OPMDs. Histopathology of the excised specimen unexpectedly revealed an in situ squamous cell carcinoma; re-excision by partial glossectomy showed no residual carcinoma, with no recurrence at 2-year follow-up. Prompted by this case, the coexistence of multiple OPMDs is proposed as a candidate risk factor (hypothesis) that could be incorporated into the leukoplakia management algorithm, supplementing existing decision trees with a branch that stratifies non-dysplastic lesions by risk factors. This case-based framework is intended to be hypothesis-generating and warrants validation in larger cohorts.