Aberrant internal carotid artery in the mouth mimicking peritonsillar abscess

The calculated incidence of aberrant internal carotid artery in the oropharynx is approximately 5% in the general population. An experienced otolaryngologist is not always available in general hospital; therefore, some invasive procedures in the oropharynx, such as aspiration, incision/drainage, and biopsy, which were performed for general infectious diseases or tissue diagnosis, may have resulted in fatal complication in these patients with misdiagnosis. We report a case to reveal that the awareness of such an anatomical variation before performing oropharyngeal procedures remains crucial. An 83-year-old woman came to our emergency department because of sore throat for several days. The physical examination showed a bulge at right peritonsillar area, and the initial impression of peritonsillar abscess was made by emergency room physician. Therefore, an otolaryngologist was consulted for abscess aspiration. However, this procedure was held after the history taking and detailed evaluation of the oropharynx performed by the consulted otolaryngologist. The patient was diagnosed as having essential hypertension with regular medication for years and a pulsatile mass at oropharynx (Fig. 1; video available). The mass pulsated regularly in the rhythm of patient's heartbeat. The computed tomographic scans showed an abnormal engorged vessel at right parapharyngeal space. Angiography revealed a redundant right cervical internal carotid artery, corresponding to the vascular structure in the retropharyngeal space (Fig. 2). There was no other vascular abnormality except some atherosclerosis. Therefore, the pulsatile mass at oropharynx was resulted from the aberrant internal carotid artery. The patient was treated with antitussive and analgesic medication for common cold. The vascular variation was clearly documented in her medical records, and the patient was notified to prevent possible injuries of the oropharynx. The study of this patient was approved by our institutional review board. Sore throat is one of the commonest presenting symptoms in general medical practices. Most upper respiratory tract infections begin with sore throat. Peritonsillar abscess, deep neck space infections, foreign bodies, and tumors of the pharynx are other usual causes of sore throat. A study performed by Market Research Society (Singapore) showed that Asians (36%) are more susceptible to catch colds than people of other regions and more likely to have sore throat, cough, stomach pain, and toothache, unlike those in North America and Latin America [1]. Patients with sore throat may visit their family physicians or an emergency ward for help first. In addition to the history taking, a detailed oropharyngeal examination is very important. Many physicians cannot examine the oropharynx of the patient clearly because of inadequate lighting, incorrect use of tongue depressor, and strong gag reflex of the patient; then the "pulsatile" mass may be omitted. If the vascular variation was misdiagnosed as peritonsillar abscess or tumors, routine emergency department procedures such as needle aspiration, incision and drainage, or biopsy may result in lethal hemorrhage. According to the descriptions in most textbooks of anatomy, the cervical part of the internal carotid artery runs a straight course to the skull base without branching. The incidence of the tortuosity, kinking, and coiling courses of the internal carotid artery in the cervical part ranged from 4% to 66% [2]. The congenital tortuosity of the artery may become more pronounced during aged life because of atherosclerotic or hypertensive changes in the wall of the vessels [3]. Physical evaluations of the lesions in the oropharynx should include manual and visual examinations in search of abnormal pulsation. The computed tomographic scans, angiography, magnetic resonance imaging, and Doppler imaging are useful modalities for demonstrating the aberrant position of the vessels [4]. It is clinically important to be aware of such anatomical variations before performing oropharyngeal manipulations or procedures such as tonsillectomy, intubation, aspiration, and drainage of abscess; therefore, we can avoid fatal complications.