aneurysm of the internal carotid artery petrous segment presenting as hypoglossal nerve palsy.
giant aneurysm of the internal carotid artery petrous segment
a 25-year-old male that first presented with 2 months of progressive left-sided headache. twenty-four hours prior to the emergency room initial evaluation patient developed tongue dysaesthesia and worsening of the headache, which was unresponsive to analgesics and non-steroidal anti-inflammatory drugs. physical examination revealed palsy of the left hypoglossal nerve (XII cranial nerve), the physical exam was otherwise unremarkable. past medical history was significant for two episodes of spontaneous pneumothorax and a remote history of heart arrhythmia. family medical history included a treated cerebral aneurysmal in his mother and two strokes on his grandfather (one of which was hemorrhagic). an mri was then performed which revealed a complex expansive mass of the left petrous internal carotid canal. The mass had a markedly heterogeneous signal, with predominantly high signal on t1 weighted images and low signal on t2 weighted images. contrast-enhanced mri and mri angiographic sequences showed ovoid dilatation of the left ica petrous segment, which was communicated with the mass described previously. a ct was later performed to better depict the aneurysmal nature of the lesion on the left ica petrous segment. the aneurysm measured 4 x 3 x 3 cm and associated extensive benign bony remodeling around its borders. Curvilinear calcifications of the vessel wall and aneurysmal near-complete filling defect was also seen. the diagnosis of thrombosed aneurysm of the left ica petrous segment was made. the expansive character of the aneurysmal sac caused complete effacement of the left hypoglossal canal and jugular foramen, which may explain the symptoms of the patient. the patient was successfully treated with flow-diverter stenting in a support institution.