Branchial remnants
Key points
2nd branchial cleft remnants - most common, 10% bilateral
7% 1st cleft remnants, 91% 2nd, 3rd + 4th very rare
90% of all cases are right sided 2nd cleft fistula
Embryology
From the branchial clefts - the 2nd pharyngeal arch should overgrow and obliterate clefts below - incomplete obliteration can lead to remnants
1st arch:
Nerve V
External auditory meatus
Tympanic cavity
Maxillary artery
Mandible, incus, malleus
Masseter, pterygoids, temporalis, anterior belly digastric
2nd arch:
Nerve VII
No normal cleft derivative
Supratonsillar fossae
Stapedial + hyoid arteries
Lesser horn + superior portion hyoid, stapes, stylohyoid process
Facial muscles
3rd arch:
Nerve IX
No normal cleft derivative - temporarily cervical sinus of His
Thymus, inferior Parathyroids
Common and internal carotids
Greater horn and inferior part of hyoid
Stylopharyngeus
4th arch:
Nerve X + superior laryngeal
No normal cleft derivative
Superior parathyroids, C-cells of thyroid
Right subclavian, left aortic arch
Laryngeal cartilages
Soft palate, cricothyroid
6th arch as 4th but:
Recurrent laryngeal nerve
Pulmonary arteries and ductus arteriosus
Branchial cysts are sometimes identified on antenatal USS - is differential for germ cell tumour, lymphatic malformation
Branchio-oto-renal syndrome associated with bilateral 2nd cleft remnants
Look for pre-auricular pits/skin tags, conductive and/or sensorineural deafness, functional or structural renal abnormalities
USS if cyst suspected
MRI if complicated
Histology of branchial cysts
Lined by respiratory or squamous epithelium
Keratinous or mucoid contents
Procedure
Wait until >1 year of age
Introduce a Prolene suture, then an elliptical incision around the opening can be done and the tract followed up with a step ladder excision. A total excision must be done
1st cleft remnant - Tract will be opening at suprahyoid near angle of mandible - through parotid deep to facial nerve - opening at external auditory meatus. Do not operate unless complicated, refer to experienced ENT surgeon
2nd cleft remnant - Tract opens anterior border of SCM - through fascia + platysma - along carotid sheath - through carotid bifurcation - posterior to posterior belly of digastric - anterior to hypoglossal nerve - close proximity to 9, 10, 11 nerves - ends in tonsillar fossa. If nerves are injured, they must be repaired
2nd cyst subtypes (Bailey classification):
Type 1: Between platysma and sternocleidomastoid
Type 2: Between sternocleidomastoid and submandibular gland, lateral to the carotid sheath
Type 3: Extends between internal and external carotid arteries
Type 4: Medial to carotid sheath, near to the tonsillar fossa
3rd - Opening at SCM (lower) - tract behind carotid - deep to the glossopharyngeal nerve - superior to the hypoglossal nerve + superior laryngeal nerve through thyrohyoid/lobe of thyroid, ends in base of piriform sinus
Difficult to distinguish from second branchial anomalies
More common on left
Near thyroid - can present with acute suppurative thyroiditis
4th - Opening at SCM (lower) - tract in tracheo-oesophageal groove - superficial to RLN, apex of piriform sinus
Mirrors the course of the recurrent laryngeal nerve, runs deep to most cranial nerves except cranial nerve XII
Right: pass posterior to the carotid artery, around the subclavian artery superficial to the recurrent laryngeal nerve and deep to the superior laryngeal nerve, past the hypoglossal nerve and into the pharynx at the pyriform sinus
Left: course is similar but passes around the aortic arch
Near thyroid - can present with acute suppurative thyroiditis
Theoretical - never been reported
3rd/4th remnants - direct laryngoscopy + contrast to evaluate for a sinus tract, standard transverse cervical incision to identify the recurrent laryngeal nerves, occasionally requiring thyroid lobectomy to excise the tract to the piriform sinus completely
Check calcium levels post op
If a patient cannot undergo surgery, ethanol ablation has been used as an alternative in this patient population, though it is not usually recommended as a primary treatment
Special scenario - Cervical cleft cyst
Impaired fusion of 1st/2nd branchial arches in the midline + improper interaction between the ectoderm and mesoderm
Thin vertical band of erythematous skin with a nipple-like projection superiorly
Found anywhere along the midline from the chin to the suprasternal notch
blind-ending sinus tract in the caudal aspect may occasionally have minimal secretion
USS to confirm diagnosis
Perform elective excision
Page edited by Mrs Charnjit Seehra BSc November 2024
References
Coste AH, Lofgren DH, Shermetaro C. Branchial Cleft Cyst. [Updated 2023 Jun 30]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK499914/
Hirschl, Ron, et al., editors. "Branchial Anomalies." Pediatric Surgery NaT, American Pediatric Surgical Association, 2020. Pediatric Surgery Library, www.pedsurglibrary.com/apsa/view/Pediatric-Surgery-NaT/829080/all/Branchial_Anomalies.
Bothra JM, Jayaram H, Deb M, Padua MDE. Congenital Midline Cervical Cleft with Respiratory Epithelium: A Rare Association. J Indian Assoc Pediatr Surg. 2018 Jul-Sep;23(3):164-166. doi: 10.4103/jiaps.JIAPS_196_17. PMID: 30050269; PMCID: PMC6042163.