Objective: To systematically review the existing literature on third branchial arch anomalies and suggest guidelines for their management.

Data sources: We searched PubMed, Medline, and Embase using Scopus, and collected additional publications cited in bibliographies. We included all English-language articles and all foreign-language articles with an English abstract.

Review methods: Two investigators reviewed all cases explicitly identified as third arch anomalies or meeting anatomical criteria for third arch anomalies; they assessed presentation, diagnostic methods, intervention, and outcome.

Results: We found 202 cases of third arch anomalies; they presented primarily on the left side (89%), usually as neck abscess (39%) or acute suppurative thyroiditis (33%). Barium swallow, direct laryngoscopy, and magnetic resonance imaging were the most useful diagnostic tools. The recurrence rate varied among the treatment options: incision and drainage, 94 percent; endoscopic cauterization of the sinus tract opening, 18 percent; open-neck surgery and tract excision, 15 percent; and partial thyroidectomy during open-neck surgery, 14 percent. Complications after surgery appeared somewhat more frequently in children eight years of age or younger.

Conclusion: Third arch anomalies are more common than previously reported. They appear to be best treated by complete excision of the cyst, sinus, or fistula during a quiescent period. Repeated incision and drainage yields high rates of recurrence and should be avoided. Complications might be minimized by first initiating antibiotic treatment, delaying surgical treatment until the inflammatory process is maximally resolved, and by using endoscopic cauterization.