Patterns of spread of squamous cell carcinoma within the mandible.

The patterns of spread of squamous cell carcinoma within the mandible were investigated in 43 nonirradiated (33 edentulous and 10 partially dentate) and 16 irradiated mandibles. Two modes of spread were identified: (1) spread in relation to the inferior alveolar nerve, and (2) spread in spaces between cancellous bony trabeculae. Although nerve-related spread was significantly more frequent in the edentulous than in the partially dentate nonirradiated mandible, the difference in incidence between all nonirradiated mandibles and irradiated mandibles was not significant. The patterns of spread in cancellous bone in irradiated and nonirradiated mandibles differed little. Spread of tumor within the medulla, deep to an intact cortex beyond the extent of extraosseous soft tissue tumor, was seen infrequently.