A Case of Incomplete Lateral Cervical Fistula Arising from the Second Branchial Cleft

We report a case of an incomplete lateral cervical fistula with an internal and external fistula connected by an intervening cord. A 77-year-old man presented to our hospital with a neck swelling and pus discharge from the swelling. Imaging revealed an external fistula and a cervical duct extending from near the anterior margin of the sternocleidomastoid muscle. No internal fistula was identified initially. The patient was diagnosed as having an incomplete lateral cervical fistula arising from the second branchial cleft, and fistula excision under general anesthesia was planned. A cord extending from the blind end of the external fistula to the upper pole of the tonsil connected to an internal fistula were identified intraoperatively. Therefore, the diagnosis of the fistula was revised to “incomplete fistula connected by an intervening cord,” and excision was performed up to near the internal fistula opening. No recurrence was apparent at 10 months postoperatively. The possibility of a continued cordate and internal fistula beyond the blind end should be borne in mind, even in patients with a preoperative diagnosis of an incomplete fistula.