Fourth branchial pouch sinus with recurrent deep cervical abscesses successfully treated with trichloroacetic acid cauterization.

A previously healthy 13-year-old girl presented with a left-sided deep cervical abscess. A CT scan demonstrated an abscess in the lower neck, anterior to the common carotid artery. Treatment with i.v. antibiotics and incision drainage resolved the condition. A recurrence of the abscess 7 months later was treated identically. Further investigations with MRI showed a 2-3-mm wide, 10-mm long structure in the lateral aspect of the left thyroid lobe. A barium radiograph depicted a narrow, 20-mm long fistula originating from the left pharynx. At endoscopy a 2-3-mm wide opening was found at the left pyriform sinus apex. This, together with the radiological findings, verified the diagnosis of a 4th branchial pouch sinus. The recurrence of the abscess may have been due to contamination by infectious pharyngeal secretions. Although radical surgical excision is traditionally recommended for this condition a non-invasive treatment, namely chemocauterization with 40% trichloroacetic acid (TCA), was chosen in this case. Three cauterizations were needed to close the pyriform sinus opening. To date (Month 14) there has been no recurrence of the cervical abscesses. TCA chemocauterization seems to be a safe first-line treatment for patients with a pyriform sinus fistula.