Introduction: Proliferative verrucous leukoplakia is an uncommon but distinctive, precursor lesion of squamous cell carcinoma. Characteristic histological features are lacking and the diagnosis is based on the combination of clinical and histological findings showing progression of the lesion. The aetiology is unknown but the rates of malignancy and recurrence are high. It is a leukoplakic plaque located in a single site, which becomes multifocal, exophytic, verrucous and with erythematous areas over the clinical course of the lesion. The most commonly affected areas are the mucosas of the alveolar ridge and palate. Cases with locations in the tongue, lips and floor of the mouth have also been reported. Case report: We here describe the clinical case of a 77-year-old woman who presented with a history of 5-year duration of a painless and extensive mass involving the palate, the alveolar ridge of the first quadrant and the base of the maxillary labial vestibule, of a whitishyellowish colour, with erythematous areas and verrucous exophytic aspect. The lesion was diagnosed as compatible with verrucous leukoplakia with severe dysplasia and foci of squamous cell carcinoma on histological examination. Discussion: Based on a clear correlation between clinical features and histological findings, the lesion was diagnosed as a proliferative verrucous leukoplakia. There is no consensus on the diagnostic criteria, as these lesions vary clinically and histologically during the clinical course, ranging from hyperkeratosis without epithelial dysplasia to squamous cell carcinoma. For this reason, many proliferative verrucous leukoplakia are not diagnosed correctly and most of them may evolve into malignancy.