Branchial Cleft Cyst



Branchial Cleft Cyst


Lester D. R. Thompson, MD










The lumen of this BrCC is filled with keratinaceous debris. There is a thin, squamous epithelium image without any atypia. There is a germinal center image within the associated lymphoid tissue.






The cyst is lined by metaplastic squamous epithelium although a residuum of columnar epithelium is still present image. There is a very thin basement membrane between the epithelium and lymphoid tissue.


TERMINOLOGY


Abbreviations



  • Branchial cleft cyst (BrCC)


Definitions



  • By convention, “branchial cleft cyst” refers to congenital developmental lateral cervical cyst derived from remnants of 2nd branchial apparatus



    • Encompasses branchial cyst, sinus, or fistula


ETIOLOGY/PATHOGENESIS


Branchial Apparatus



  • Precursor of many head and neck structures


  • 2nd branchial arch overgrows 2nd, 3rd, and 4th clefts


  • This overgrowth forms “cervical sinus”


  • Embryogenesis is usually complete by 6-7 weeks of gestation


  • Failure of obliteration of cervical sinus results in 2nd branchial cleft remnant (cyst, sinus, or fistula)


  • 2nd branchial cleft fistula extends from skin anterior to sternocleidomastoid muscle (SCM), through carotid artery bifurcation to terminate in tonsillar fossa


  • 3rd and 4th branchial cleft cysts are very uncommon (< 5%)



    • Recurrent neck abscess or acute suppurative thyroiditis


    • Vast majority on left side (90-95%)


  • Some posit cystic transformation of cervical lymph nodes



    • Especially in adults


CLINICAL ISSUES


Epidemiology



  • Incidence



    • Uncommon



      • Still, BrCC is one of the most commonly encountered congenital anomalies in pediatric otolaryngic practice


      • Thyroglossal duct cysts are most common


    • BrCC accounts for ˜ 20% of all congenital cervical cysts



      • Cysts > > sinuses (3:1)


    • About 80-90% of all branchial cleft anomalies are 2nd branchial cleft cysts


  • Age



    • Bimodal presentation



      • < 5 years old (25%)


      • 20-40 years old (75%)


      • ˜ 1% in patients > 50 years old


  • Gender



    • Equal sex distribution


Site



  • Lateral neck near mandibular angle


  • Along anterior border of SCM



    • Anywhere from hyoid bone to suprasternal notch


  • Curiously, left-sided predominance for 4th branchial anomalies (> 90%)


Presentation

Jul 8, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Branchial Cleft Cyst
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