Isolated hypoglossal nerve palsy: a diagnostic challenge.

was admitted to our hospital for an additional workup. Until then speech difficulties had diminished, but he reported occasional vague pain localized to the right mandibular angle, especially during head movements. There was no history of neck trauma or manipulation or vigorous exercise. Neurological examination revealed only right HNP with ipsilateral atrophy ( fig. 1 ) without signs of other cranial nerve palsies as well as pyramidal signs or Horner syndrome. The patient was otherwise in excellent general condition. His medical history was unremarkable. Routine blood analysis was normal. Needle electromyography of the tongue showed denervation changes in the muscles supplied by the right hypoglossal nerve, whereas electromyographic findings in the left side of the tongue and cervical muscles were normal. Computed tomography (CT) of the brain and the base of the skull was unremarkable. In the T 1 -weighted MRI images without fat suppression before and after administration of gadolinium which were performed 3 weeks after the onset of symptoms, a hyperintense, round, 15mm-wide pseudoaneurysm of the right internal carotid artery was found with hypointensity in the central part of the lesion representing the residual lumen of the artery ( fig. 2 ). The lesion extended approximately 25 mm distal to the right carotid artery bifurcation up to the entrance of the internal carotid artery in the carotid Dear Sir, Hypoglossal nerve palsy (HNP) is not an uncommon finding in neurological diseases [1] . However, when isolated, HNP can represent a diagnostic challenge in everyday clinical work and is limited to isolated case reports and few small case series [2] . In this article, we report 4 patients with clinical presentation of isolated HNP due to different etiologies.