Extracranial carotid aneurysms are rarely seen. 1-3 They con- stitute 0.4% to 4% of all aneurysms. The causative factor in most cases is atherosclerosis. 1 They are less frequently seen with trauma, infection, cystic medial necrosis, neoplasms, fibromuscular dysplasia, and Ehlers-Danlos syndrome. 1,2 A case of an infectious pseudoaneurysm of the right external carotid artery is presented. CASE REPORT A 17-year-old girl with fever and malaise had received an unknown antibiotic therapy for 10 days elsewhere. Because her symptoms had increased, she received 2 more different unknown antibiotic treatments with the diagnosis of sepsis. Her medical status deteriorated, and she was referred to another hospital with the diagnosis of pneumonia and adult respiratory distress syndrome. Laboratory findings were as follows: ery- throcyte sedimentation rate (ESR), 35 mm/hour; white blood cell count (WBC), 31,000/mm 3 ; and high WBC in the urine. Hemoculture and tests for tuberculosis (PPD and chest x-ray film) were negative. She was treated with nonspecific antibio- therapy, mechanic ventilation, and blood transfusion, and she was discharged after 20 days of hospitalization. On the day she was discharged, she had right otalgia, hoarseness, and a 2-cm mass below the lobule; she received another antibiotic for 10 days. After this treatment her symp- toms increased gradually, and she had headache and dyspha- gia. The patient was admitted to our clinic and hospitalized for further investigation and treatment. Examination of her neck revealed a tender, pulsatile, smooth-surfaced, and hyperemic mass occupying the parotid, submandibular, and carotid regions extending to the greater cornu of the hyoid bone inferiorly with a dimension of 8 × 8 cm. Examination of the oropharynx revealed that her right tonsil and lateral pharyngeal wall were displaced medially. Indirect laryngoscopy showed restricted mobility of the ary- tenoid. The mandibular branches of the right facial nerve and glossopharyngeal and hypoglossal nerves were paralyzed. Other clinical and laboratory findings were normal. Chest x-ray film, ultrasonography (USG) of the abdomen, and CT of the thorax were normal. There was an aneurysmal formation with a severe turbulent flow showing the pattern of the thrombotic component of the aneurysm during Doppler USG of the mass. The CT scan of the neck showed a lobulated, contoured aneurysmal mass of the right external carotid artery suggesting a pseudoaneurysm (Fig 1). Dense contrast filling with thrombotic parts in it were detected. The aneurysmal mass displaced the parotid gland laterally and the mandibular ramus anterolaterally and extended to the parapharyngeal space and the infratemporal fossa. The MRI of the neck revealed an aneurysmal mass of the right external carotid artery with a heterogeneous structure indicating a turbulent flow and hyperintense region belonging to the thrombotic component at the periphery of the aneurysm (in T 1 - and T 2 - weighted scans). Selective angiography of the right common carotid artery revealed an irregular contoured pseudoaneurysm of the exter- nal carotid artery distal to the superior thyroid artery with a diameter of 7 cm. In the cerebral CT scan there was an abscess formation with a dimension of 2 cm medial to the left posteri- or parietal space (water-shed infarct region) and a focal area of cerebritis at the periphery of the abscess. In the operation a Montgomery incision with an extension to the mentum was used. An aneurysmal sac was found to begin just from the upper limit of the superior thyroid artery and to fill the carotid, submandibular parotid region and the parapharyngeal space. The sac was full of thrombus, was adherent to the surrounding structures, and had an irregular border. The right hypoglossal, buccal, and cervicomandibular branches of the facial nerve were surrounded by the pseudoa- neurysm. The external carotid artery was ligated just distal to the bifurcation. A total parotidectomy was performed, and the buccal and cervicomandibular branches of the facial nerve and the distal portion of the hypoglossal nerve were dissected free from the mass. The pseudoaneurysm was also seen to fill the parapharyngeal space. It was freed from the surrounding structures and totally removed. Postoperative histopathologic examination was reported to be a pseudoaneurysm with thrombus. No microorganisms could be found in the bacterio- logic examination (aerobe and anaerobe cultures). Postoperative follow-up was uneventful, and the patient was discharged on the 10th day. The ischemic area in the left Giant external carotid artery pseudoaneurysm presenting as a parotid mass M. ZAFER U ˇ GUZ, MD, KAZ ˙ IM ÖNAL, MD, SEMIH ÖNCEL, MD, ˙ ILHAN TOPALO ˇ GLU, MD, NEZAHAT ERDO ˇ GAN, MD, ALI ÖZER, MD, and HÜNKAR GÖKÇE, MD, ˙ Izmir, Turkey 307 From the Departments of Otolaryngology (Drs Uˇ guz, Önal, Öncel, Topaloˇ glu, Ali Özer, and Gökçe) and Radiology (Erdoˇ gan), ˙ Izmir State Hospital. Reprint requests: M. Zafer Uˇ guz, MD, 108/25 S. No: 4/5, Esendere, 35350 ˙ Izmir, Turkey Otolaryngol Head Neck Surg 2000;122:307-9. Copyright © 2000 by the American Academy of Otolaryngology– Head and Neck Surgery Foundation, Inc. 0194-5998/2000/$12.00 + 0 23/78/98316