Management of a First Branchial Cleft Fistula in an Adult Patient: A Case Report and Literature Review

Abstract

First branchial cleft anomalies (FBCAs) are uncommon congenital malformations that develop due to incomplete closure of the first branchial cleft during embryonic development. They represent a small proportion of all branchial cleft anomalies. These lesions, which may present as cysts, sinuses, or fistulas, pose significant diagnostic and therapeutic challenges due to their nonspecific clinical manifestations and complex anatomical relationships, particularly with the facial nerve and parotid gland. This case report describes a 47-year-old male patient presenting with recurrent infections and purulent discharge in the right preauricular and submandibular regions, later diagnosed as a Work Type II first branchial cleft fistula extending from the external auditory canal (EAC) through the parotid gland to the submandibular skin. Diagnostic evaluation included high-resolution magnetic resonance imaging (MRI) and computed tomography (CT) fistulography, which confirmed the fistula's course and its intimate relation to the facial nerve. Surgical management involved complete excision via a modified Blair incision, retrograde facial nerve dissection, and superficial parotidectomy, with intraoperative neuromonitoring to minimize nerve injury risk. Histopathology revealed a cutaneous fistulous tract lined with stratified squamous epithelium and sparse chronic inflammatory infiltrates. Postoperative recovery was uneventful, with transient House-Brackmann grade II facial nerve palsy resolving within four weeks and no recurrence at the 12-month follow-up. This case is notable for the patient's unusually late presentation in adulthood, contrasting with the typical diagnosis in childhood. A comprehensive literature review highlights the embryological basis, clinical variability, and diagnostic challenges of FBCAs, emphasizing the critical role of preoperative imaging for delineating the fistula's anatomy and planning surgery. Complete surgical excision with facial nerve preservation remains the gold standard, though the procedure is complicated by the lesion's proximity to critical neurovascular structures. Intraoperative neuromonitoring and patient-specific surgical approaches are essential to minimize complications such as facial nerve palsy and recurrence. This case underscores the importance of timely diagnosis, meticulous preoperative planning, and specialized surgical expertise in achieving favorable outcomes for FBCAs, particularly in atypical adult presentations.

Keywords: branchial region; congenital abnormalities; facial nerve; fistula; parotid gland.

Figure 1. MRI showed an intraparotid lesion in the superficial layer, resembling a fistula (green arrows). The fistula tract varied in diameter, with the widest part measuring 1.6 cm in the middle. The external auditory canal and right tympanic membrane appeared normal, indicating no involvement of these structures. Nearby ear structures were not affected.

(a) T2 sequence, coronal view; (b) T1 sequence, coronal view; (c) T1 sequence, axial view

Figure 2. CT fistulography

The green arrows depict a fistula with a maximum diameter of 1.6 cm, starting from the external auditory canal, continuing through the parotid tissue, and ending in the right submandibular skin region (a, b, and c show the coronal view).

Figure 3. CT fistulography

The green arrows depict the course of the fistula with a maximum diameter of 1.6 cm, starting from the external auditory canal, continuing through the parotid tissue, and ending in the right submandibular skin region (pane a shows the coronal view); (b and c) 3D rendering images show again the course of the fistula, demonstrating hard and soft tissue structures, respectively.

Figure 4. CT fistulography

The green arrows reveal the fistula and its relation to the external auditory canal; (a) axial view, (b) coronal view.

Figure 5. Clinical presentation of the branchial cleft fistula

(a) The fistula passing through the parotid tissue with a course under the main trunk of the facial nerve; (b) The fistula after being dissected, with part of the parotid tissue after careful removal from the facial nerve. The yellow arrows depict the branchial cleft fistula.

Figure 6. Clinical presentation of the branchial cleft fistula

(a) The distal stroma of the fistula, situated in the anterior wall of the external auditory canal, was identified and completely removed (yellow arrow), facial nerve (white arrow); (b) The excised specimen, with a total length of 9 cm.

Figure 7. (a) Sinus tract covered by stratified squamous epithelium without atypia (hematoxylin and eosin, ×40); (b, c) fibrous connective tissue forming the wall of the sinus tract, without associated chronic inflammatory infiltrate or granulation tissue. Blue arrows depict the course of the track (hematoxylin and eosin, ×100).