Hypoglossal nerve palsy in nasopharyngeal carcinoma.

The carotid space and the last four cranial nerves are at risk when nasopharyngeal carcinoma (NPC) recurs or spreads posterolaterally. The objective of this study is to document the features of hypoglossal nerve infiltration and the appearance of the paralysed tongue. We reviewed hypoglossal nerve palsy in 16 patients with NPC. The following features were analysed: tumour morphology (submucosal spread), hypoglossal canal erosion, perineural infiltration or intracranial spread, other lower cranial nerve palsies, and appearance of the tongue. These findings were correlated with clinical records. All 16 patients had tumour recurrence following radiation therapy. In 7 patients (44 %), recurrence was submucosal. Hypoglossal canal involvement was seen in 12 patients (75 %). Isolated hypoglossal nerve palsy was noted in 5 patients (31 %) and 7 patients (44 %) had posterior cranial fossa tumour spread. Posterior displacement of the tongue was consistently well seen. In conclusion, tumour recurrence should be suspected in the presence of hypoglossal nerve palsy even when endoscopic findings are negative. Posterior displacement of the tongue, which has not been emphasised in the literature, is an easily recognisable sign and may indicate early hypoglossal nerve palsy.