Mandibular invasion by squamous cell carcinoma: a computed tomographic and histological study.

Our knowledge of the entry and spread of oral cell carcinoma (SCC) into the mandible is increasing, making an impact on surgical planning. Fourteen resection specimens of mandibular bone and adjacent SCC were radiographically (CT) and histologically investigated. In six cases there was no involvement of mandibular bone; a continuous periosteal layer separated the tumour from bone. The remaining eight specimens showed bony involvement with good correlation between corresponding CT and histological slices in the five edentate cases. The site of entry of the tumour into the bone was usually through the alveolar crest with additional spread through the lingual cortex in tumours that lay lingual to the mandible. Although limited, our data shows that the main site of entry of SCC is through the alveolar crest. It also highlights the usefulness of CT in the identification of bone involvement in edentate cases. This information may assist in the planning of operations to preserve as much bone as is consistent with complete excision of the tumour.