Growth characteristics of ameloblastoma involving the inferior alveolar nerve: a clinical and histopathologic study

OBJECTIVE: Growth characteristics of ameloblastomas involving the inferior alveolar nerve were examined to determine the most appropriate surgical management of the nerve at the time of the surgical procedure. STUDY DESIGN: Clinical and histopathologic examinations were performed on 22 resected mandibles in which the inferior alveolar nerve was lying adjacent to, or contained within, the tumor. RESULTS: Patterns of tumor involvement of the nerve bundle were evaluated with respect to the presence of bone (11 patients) or connective tissue wall (7 patients) between the tumor and the nerve bundle, and tumor infiltration of perineural connective tissue (4 patients). Neither invasion into the nerve sheath nor invasion into the nerve itself by the ameloblastoma was detected. Tumor infiltration of the tissue surrounding the nerve was identified for the multicystic and solid types but not for the unicystic type. Presence of bone or connective tissue wall between the tumor and the nerve bundle was dominant in the unicystic and plexiform ameloblastomas, whereas tumor infiltration of the perineural tissue was frequently observed in ameloblastomas with the follicular pattern. CONCLUSION: The preservation of the inferior alveolar nerve may be possible in the management of the unicystic type of ameloblastoma. However, a more radical approach is necessary for treatment of multicystic or solid tumors, especially those exhibiting a follicular pattern.