Branchial Cleft Sinuses and Cysts



Branchial Cleft Sinuses and Cysts


Mark Felton

Jugpal S. Arneja

Neil K. Chadha





ANATOMY



  • Branchial arches are akin to ancient gill apparatus (FIG 1).


  • Humans have five branchial/pharyngeal arches, 1 to 4 and 6 (there is no 5th branchial arch), which form craniocaudally from week 4.


  • Membrane ectoderm externally and endoderm internally covers the arches.


  • Cleft externally separates each arch.


  • Pouch internally separates each arch.


  • Each arch forms an artery, cartilaginous structure, nerve and muscle.


  • Arches 1 and 3 mainly form the face, and arches 3, 4, and 6 form the neck, with 4 and 6 fusing.


  • Ectodermal clefts obliterate except for the 1st branchial cleft, which forms the external auditory canal with outer side of the tympanic membrane forming the medial limit.


  • Branchial pouches form various head and neck organs (Tables 1 and 2).






FIG 1 • Branchial arch and pouches.


PATHOGENESIS



  • Failure of branchial pouch or cleft to obliterate during embryonic development can lead to fistula, sinus, or cyst formation:



    • A cyst is an epithelial-lined fluid-filled sac.


    • A sinus is a blind-ended epithelial lined tract opening on to skin or mucosa.


    • A fistula is an epithelial-lined tract connecting two surfaces (skin/mucosa).


  • The resultant anomaly from failure of this process relates to the specific arch, pouch or cleft derivatives.


  • The main branchial anomalies associated with sinuses and fistulae are 1st and 2nd cleft anomalies and 3rd and 4th pouch anomalies.


  • Type 1 branchial anomalies are rare anomalies resulting in duplication of the external ear canal and are classified as Work’s type 1 or 2.


  • Branchial cleft cysts are regarded as 2nd branchial anomalies. Several theories exist as to their origin including3:



    • Lymph node inclusion theory—cystic transformation of lymph nodes


    • Branchial cleft remnant theory—remnant of branchial cleft/pouch


    • Thymopharyngeal duct theory—remnant of the connection between the thymus and 3rd pouch


    • Cervical sinus of His theory—cyst is formed by remains of the cervical sinus.


PATIENT HISTORY AND PHYSICAL FINDINGS



  • Branchial sinuses and fistulas may present as a discharging neck punctum +/- neck swelling.


  • Type 1 branchial anomaly is rare.



    • Often a late diagnosis


    • May present with a mass in parotid or submandibular region


    • Discharging neck punctum or discharging ear


  • Type 2 branchial anomalies are the most common branchial anomaly.



    • Often present at or just after birth


    • External opening in the skin (punctum) along anterior border sternocleidomastoid muscle +/- discharge


  • Type 3 and 4 brachial sinus



    • Neonates—lateral neck cyst/abscess +/- airway obstruction


    • Child/young adult—thyroiditis/recurrent neck abscess


    • Most commonly diagnosed in childhood (delayed diagnosis)


  • Branchial cysts



    • May present as a cystic neck swelling +/- infection/abscess









      Table 1 Branchial Arch and Pouch Derivatives
















































      Arch Derivatives


      Pouch Derivatives


      Artery


      Cartilage


      Cranial Nerve


      Muscle


      1


      Part of terminal branches maxillary artery


      Meckel cartilage: malleus and incus, anterior malleolar ligament, mandible template, maxilla, zygomatic bone and squamous temporal bone, mandible


      V—trigeminal


      Muscles of mastication, mylohyoid, tensor tympani, anterior belly digastric


      Tubo-tympanic recess, tympanic cavity, mastoid antrum, Eustachian tube


      2


      Stapedial arteries


      Reichert cartilage: stapes, styloid process, stylohyoid ligament, lesser cornu, and superior body of hyoid


      VII—facial


      Muscles of facial expression, stapedius, stylohyoid, posterior belly digastric


      Tonsils


      3


      Common carotid arteries, internal carotid arteries


      Greater cornu and inferior part of hyoid


      IX—glossopharyngeal


      Stylopharyngeus


      Inferior parathyroid glands and thymus


      4


      Left forms part of aortic arch, right forms part right subclavian artery


      Laryngeal


      X—vagus, superior laryngeal


      Cricothyroid, pharynx constrictors


      Superior parathyroid glands and possibly the calcitonin-producing cells of thyroid


      6


      Pulmonary arteries, ductus arteriosus


      Laryngeal


      X—vagus, recurrent laryngeal


      Intrinsic muscles of larynx




    • Peak age 3rd decade


    • Most are located anterior to the upper part of the sternocleidomastoid muscle


  • Branchio-oto-renal syndrome is an autosomal dominant syndrome with a prevalence of 1 in 40 000 people. It is caused by mutations in the EYA1, SIX1, and SIX5 genes.4


  • Children born with this typically have branchial anomalies, ear abnormalities (including pits, tags, atresia, hearing loss) and kidney abnormalities (including hypoplastic/absent kidneys). If suspected, these children require audiometry, an ultrasound of the renal tract, and genetic counseling.


IMAGING



  • Imaging varies depending on the branchial anomaly.


  • Cysts—ultrasound (USS) is obtained usually, but an MRI may be helpful when the diagnosis is not clear on USS.


  • Type 1—CT to image middle ear and MRI for soft tissues and course of sinus/fistula (FIG 2A).


  • Type 2—clinical diagnosis; usually no imaging required.


  • Types 3 and 4—barium swallow/and direct laryngoscopy to assess for sinus/fistula entrance at the pyriform fossa; USS +/- MRI to assess thyroid involvement and any cystic component (FIG 2B).






Table 2 Pathophysiology and Sinus/Fistula Course

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Feb 27, 2020 | Posted by in Pediatric plastic surgery | Comments Off on Branchial Cleft Sinuses and Cysts
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