title: Isolated hypoglossal nerve palsy: a harbinger of malignancy.
abstract: The hypoglossal nerve is an underrated nerve usually consigned to a few words in anatomical text books, under the last four cranial nerves. However, paralysis of this nerve may be the first indication of a serious underlying disorder. Excluding previous surgery, radiotherapy and trauma, 50 per cent of cases of isolated hypoglossal nerve palsy are idiopathic. A further 20 per cent are malignant, 20 per cent are vascular and 10 per cent are due to miscellaneous causes. Presentation of an isolated hypoglossal nerve palsy is therefore an ominous sign. There is confusion over both cause and investigation, and management protocols for isolated hypoglossal nerve palsy are ill-defined. We present a case of isolated hypoglossal palsy which was due to a metastatic skull base deposit. This case illustrates the fact that magnetic resonance imaging is the investigation of choice in assessing the entire course of the hypoglossal nerve.
authors.affiliation: Department of Otolaryngology/Head and Neck Surgery, Mid-Western Regional Hospital, Limerick, Ireland. sgkhoo@hotmail.com
authors.forename: S G
authors.initials: SG
authors.lastname: Khoo
authors.forename: I
authors.initials: I
authors.lastname: Ullah
authors.forename: F
authors.initials: F
authors.lastname: Wallis
authors.forename: J E
authors.initials: JE
authors.lastname: Fenton
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis* / Q000556:secondary; D003390:Cranial Nerve Neoplasms / Q000175:diagnosis* / Q000556:secondary; D017809:Fatal Outcome; D005260:Female; D006801:Humans; D020437:Hypoglossal Nerve Diseases / Q000175:diagnosis* / Q000209:etiology; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D019292:Skull Base Neoplasms / Q000175:diagnosis* / Q000556:secondary