Aberrant retropharyngeal internal carotid artery associated with retropharyngeal abscess: determination of a safe drainage zone with CT.

A 60-year-old woman visited the Ear Nose and Throat (ENT) department of our hospital complaining of sore throat that persisted since 2 weeks. She was prescribed oral antibiotherapy, during which she experienced dysphagia and increasing fever. After physical reexamination and endoscopic study, a retropharyngeal abscess was detected and was thought to be due to the bulging of the right posterior pharyngeal wall that has smooth and intact mucosa. Thus, the patient was forwarded to the radiology department for enhanced neck computed tomography (CT) to confirm the diagnosis. On the multidetector neck CT scan, we observed an abscess formation (thick white arrow) with peripheral contrast enhancement, and enlargement of the right retropharyngeal space was also seen (Fig. A). In addition, the CT images also displayed an aberrant course of the right internal carotid artery (ICA) (thin white arrows) that was very close to the right posteromedial wall of the pharynx and contributed to the enlargement of the retropharyngeal space (Fig. B, C).