Branchial cleft cysts are a benign anomaly caused by incomplete obliteration of a primordial branchial cleft. They typically appear in childhood or adolescence, but can appear at any age. They present as a non-tender, fluctuant mass following an upper respiratory infection, most commonly at the anterior border of the sternocleidomastoid muscle. These lesions are thought to originate during the 4th week of gestation when the branchial arches fail to fuse. The second branchial cleft is the most common site (95%) and cysts from in this distribution can affect cranial nerves VII, IX, and XII.
Horizontal incision location is marked at the level of the cyst and infiltrated with 1:1000 lidocaine with epinephrine. Incision is made and subplatysmal flaps are raised. Bluntly dissect to the superior and inferior edges of the cyst, meanwhile identifying marginal mandibular and hypoglossal nerves. Stimulate facial nerve branch to confirm safety. Use blunt dissection to free cyst from surrounding tissue and identify tract running deep to lesion. Tie off tract with suture and remove cyst in its entirety. Close in layers with watertight seal at the skin level.
Presence of a branchial cleft cyst.
If a cyst is found during an active infection, adequate time should be taken for the infection to resolve prior to the procedure.
Facial nerve monitoring with a NIM monitor can help avoid inadvertent consequences.
Imaging is indicated to rule out malignant process and for surgical planning. CT scans are effective in determining size and extent of lesion. Ultrasonography can be effective especially in larger cysts. MRI can also be effective but is usually reserved for more complex cysts of the first branchial cleft. Imaging will show a cystic, well circumscribed lesion that enhances with contrast.
Second branchial cleft cysts run through several identifiable structures. They typically pass between internal and external carotid arteries, deep to cranial nerve VII and near cranial nerves IX and XII.
Adequate treatment and closure of any fistula tract will prevent recurrence.
Several nerves are at risk of injury during this procedure. Facial nerve monitoring with special attention paid to the marginal mandibular and cervical branches will be helpful for second branchial cleft cysts. The glossopharyngeal and hypoglossal nerves can also be damaged by retraction or instrumentation.
Allen SB, Jamal Z, Goldman J. Branchial Cleft Cysts. [Updated 2022 Jul 24]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK482467/