Resorption of impacted teeth as a marker of squamous cell carcinoma infiltrating the mandible

The invasion of the mandible by oral squamous cell carcinoma has been firmly demonstrated by anatomical and histological studies. Although squamous cell carcinomas may induce resorption of the roots of standing teeth, there have been no reports of them also causing resorption of the crowns of teeth. A 73year-old patient presented with an invading buccal squamous cell carcinoma. Radiological investigations showed tumour invasion of the dentate region of the left mandible and resorption of the crowns of right and left mandibular impacted third molars. The patient underwent a left segmental mandibulectomy and histopathological examination of the resected specimen revealed resorption of the enamel and dentine of an unerupted impacted third molar closely associated with the infiltrating tumour. Thus infiltrating carcinomas may rarely cause resorption of the crowns as well as the roots of unerupted teeth and can be a valuable marker of the extent of spread of a tumour for the planning of complete surgical resection. These dental changes must be distinguished radiologically from idiopathic changes in unerupted teeth in the absence of malignancy.