The Sixth Cranial Nerve Paralysis Caused by Nasopharyngeal Cancers

ABSTRACT

PURPOSE: To investigate cases of the nasopharyngeal cancer with the sixth cranial nerve paralysis and review the current literatures on the nasopharyngeal cancer and the sixth nerve paralysis. METHODS: We analysed retrospectively clinical characteristics of 41 patients diagnosed with the nasopharyngeal cancer from January 1994 to December 2000. RESULTS: In 41 patients with the nasopharyngeal cancer, 6 patients (14.6%) had the sixth cranial nerve involvement. 4 patients of them visited ophthalmologic department after diagnosed with nasophryngeal cancer with symptom of neck mass or tinnitus. 2 patients visited ophthalmologic department and then were diagnosed with nasopharyngeal cancer with magnetic resonance imaging and biopsy. CONCLUSIONS: The sixth cranial nerve paralysis may be caused by trauma, intracranial disorder (tumor, meningitis, demyelination), vascular disorder, diabetes, hypertension, and viral illnesses. We emphasize the suspicion for the possibility of the nasopharyngeal cancer in patients with unexplained sixth cranial nerve paralysis causing diplopia and limitation of extraocular muscle.