Fourth branchial cleft cyst with no identifiable tract: case report and treatment approach.

: We describe a rare case of a fourth branchial cleft cyst that had no identifiable tract. The patient was a 23-year-old man who presented with recurring neck abscesses. After six similar episodes, computed tomography finally demonstrated that the most recent abscess had extended into the thyroid gland, a finding that led to the correct diagnosis. Extensive surgical extirpation of the cyst with an adjacent neck dissection was performed, and the patient remained symptom-free at 25 months of follow-up. The occurrence of a fourth branchial cleft cyst with no clear tract presents a surgical dilemma, as complete dissection cannot be guaranteed. Consequently, such patients are predisposed to recurrence. We propose that definitive management of a fourth branchial cleft cyst with no identifiable tract focus on eliminating the likely embryologically based path of bacterial seeding. This includes a hemithyroidectomy in conjunction with a selective neck dissection to cover all areas where a fourth branchial tract may lie within the neck.