THE DISSEMINATION OF TUMORS OF THE HEAD AND NECK VIA THE CRANIAL NERVES

Abstract

Malignant tumors may spread through the perineural and endoneural spaces of the regional nerves. Although the clinical symptoms may be remarkably mild, local neurologic abnormalities should always be considered to be due to neural invasion. An analysis of 40 cases of head and neck cancers has indicated that this form of metastatic disease is most frequently seen with recurrent or advanced tumors. Initial treatment may be inadequate because neural invasion is unrecognized, or neural involvement may result from an inadequately treated tumor. Radiologic exploration of the intraosseous portions of the fifth and seventh nerves has proven useful in the diagnosis of perineural and endoneural invasion. An increase in the diameter of the nerve may be reflected by erosion of one or more foramina or canals. In instances of clinically suspected or radiographically demonstrated neural involvement, serial frozen sections should be made during the surgical procedure until disease-free nerve is encountered or evidence of intracranial extension is obtained. Several of the patients in this series have been salvaged as a result of surgical or radiographic recognition of neural metastases. Undoubtedly, infiltration of the regional nerves will continue to be responsible for some treatment failures. However, we believe that an increasing number of patients may benefit if this form of metastatic disease is appreciated and appropriate diagnostic and therapeutic measures are instituted.