Internal carotid artery dissection presenting with ipsilateral tenth and twelfth nerve palsies and apparent mass lesion on MRI.

We report the case of a 47-year-old man who presented with a few months' history of right-sided headache and dysphagia, with ipsilateral tenth and twelfth cranial nerve palsies on examination. The initial MRI showed an enhancing mass lesion in relation to the right carotid sheath and jugular foramen, and was reported as a possible paraganglioma. Subsequent angiography performed to assess tumour vascularity demonstrated a dissection involving a tonsillar loop of the right internal carotid artery (ICA). Imaging findings at MRI and angiography and the presentations and mechanisms of ICA dissection are briefly discussed.