The lateral standard cervical x-ray film showed an increased thickness of the retropharyngeal soft tissue. Contrast-enhanced computed tomograms revealed an area of low attenuation with a complete circumferential rim of enhancement extending from the piriform sinus to the retropharyngeal space and the right thyroid space.
Malformations of the fourth branchial pouch are the rarest of all branchial cervical malformations.1 Sandborn and Shafer2 published the first clinical description and embryological study of a branchial cleft cyst of fourth pouch origin in 1972, but there is still a lack of understanding in this area. It is generally agreed that fourth branchial pouch sinuses are caused by abnormal development of the pharyngobranchial sinus in the fourth week of fetal life. The left predominance of these malformations is clearly linked to the asymmetrical growth of the fourth arch owing to vascular development.3 Therefore, in a review of the literature, we found that 83% to 97% of these abnormalities occurred on the left side.4
Radiology Quiz Case 1: Diagnosis. Arch Otolaryngol Head Neck Surg. 2009;135(9):942-943. doi:10.1001/archoto.2009.133-b