Female, 65 years old, status post isthmusectomy and neck exploration for possible branchial arch track involving the left peripheral sinus, now undergoing preoperative imaging for thyroidectomy and repeat neck dissection. The left piriform sinus is effaced due to thickening of the adjacent hypopharyngeal mucosa as well as anterior displacement of that mucosa. This mucosal displacement appears to be related to a band of T2 hyperintense, mildly enhancing tissue situated posterior to the pharynx, beginning just above the level of the piriform sinus and continuing approximately 3 cm inferiorly reaching to the level of the left thyroid bed. On prior CT examinations, there was a rim-enhancing fluid collection which occupied approximately this same territory. No discrete or rim-enhancing fluid collections are seen on today's exam. No pathologic adenopathy is observed. The thyroid gland is small which may be related to prior surgery. The salivary glands are free of suspicious focal lesions. There may be a small esophageal diverticulum which projects anteriorly, along the left posterior margin of the trachea, heading towards the left thyroid bed.
A band of thickened, solidly enhancing tissue is evident spanning from just behind the hypopharynx at the level of the left piriform sinus, down to the level of the left thyroid bed. On prior examinations, there was a rim-enhancing collection which occupied this territory. The solid tissue on today's examination may represent scarring or granulation related to prior inflammation. The location and general trajectory of this tissue would be compatible with a fourth branchial apparatus anomaly. There may also be a small esophageal diverticulum which projects anteriorly toward the left thyroid bed.