Thyroid gland
Congenital anomalies
Branchial pouch / cleft anomalies

Author: Andrey Bychkov, M.D., Ph.D. (see Authors page)

Revised: 29 August 2015, last major update August 2015

Copyright: (c) 2003-2015, PathologyOutlines.com, Inc.

PubMed Search: Branchial pouch [title] thyroid
Definition / General
  • Congenital lesions due to incomplete obliteration of the branchial apparatus
  • May be cyst, sinus, fistula or cartilage in anterolateral neck
  • Cysts derived from branchial cleft have squamous epithelium; cysts derived from branchial pouch have respiratory epithelium, although repeated infections may cause squamous metaplasia (Ann R Coll Surg Engl 2007;89:W12)
  • Terminology
  • A sinus is a blind ending tract
  • "Branchial cleft sinus" connects to the skin, but a "branchial pouch sinus" connects to the pharynx; neither arises from the mesenchyme of the branchial arch (J Laryngol Otol 2004;118:19)
  • A "true fistula" is a communication between two epithelialized surfaces; a "congenital branchial fistula" should be present at birth and should communicate between a persistent pouch and a cleft
  • Most of the branchial fistulas are pseudofistulas, formed between a pouch remnant and a skin opening produced following an infection or a surgical incision, or are just sinuses (AJNR Am J Neuroradiol 2010;31:755)
  • Epidemiology
  • 20-40 years old, M = F
  • 20% of cervical masses in children (Int J Pediatr Otorhinolaryngol 2011;75:1020)
  • Cysts: fistulas = 10:1 ( Eur J Inflamm 2012;10:39)
  • 2-3% are bilateral (Ear Nose Throat J 2008;87:291)
  • Sites
    Sites of cysts:
    • First branchial cleft: 5-8%; preauricular area (type I cyst) or below the angle of mandible (type II), may be connected to external auditory canal; these cysts are rarely malignant (Diagn Cytopathol 2008;36:876)
    • Second branchial cleft: 95%; anterior to sternocleidomastoid muscle in midneck, may communicate with pharynx (Singapore Med J 2015;56:203)
    • Third / fourth branchial cleft: 2-5%; suprasternal or supraclavicular neck
      • May be misdiagnosed as bronchogenic cyst
      • Usually left sided and associated with neck infection
      • Treatment is ipsilateral thyroidectomy as lesions pass through thyroid
    Diagrams
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    Branchial apparatus

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    Branchial cleft fistulas

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    Branchial cleft anomalies location

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    Anatomical relations

    Pathophysiology / Etiology
  • Branchial theory suggests that incomplete obliteration of branchial cleft mucosa, which remains dormant until stimulated to grow later in life, results in cyst formation (Ascherson, 1832) (Am J Pathol 1967;50:533)
  • More theories: persistence of vestiges of the precervical sinus, thymopharyngeal duct origin and cystic lymph node origin (J Am Dent Assoc 2003;134:81)
  • Clinical Features
  • Slow growing movable mass in the lateral neck, often asymptomatic
  • Presents as inflammatory neck mass or fistula
  • Rarely associated with squamous cell carcinoma (J Laryngol Otol 1994;108:1068), but cystic neck masses should be considered to be nodal metastases until proven otherwise (common sites of small primary occult tumors are tonsil, posterior tonsillar pillar, retromolar tongue, nasopharynx)
  • Clinical branchial cysts may rarely:
  • Diagnosis
  • Imaging and fluoroscopic fustulography to visualize cyst / fistula and anatomic tract
  • Pyriform sinus examination via direct laryngoscopy to detect third / fourth branchial cleft anomaly
  • Radiology
  • Ultrasound: low echogenic lesion with lack of internal septation
  • CT scan and MRI require sedation in children
  • Prognostic Factors
  • Recurrence rate depends on completeness of resection, mean 5% (Dentomaxillofac Radiol 2012;41:696)
  • Case Reports
  • 18 month old child with third branchial pouch cyst presenting as stridor (Ann R Coll Surg Engl 2007;89:W12)
  • 9 year old boy and 42 year old man with fourth branchial complex anomaly (Case Rep Otolaryngol 2011;2011:958652)
  • 10 year old girl with branchial cleft cyst at an unusual location (Dentomaxillofac Radiol 2012;41:696)
  • 12 year old girl with type II first branchial cleft anomaly presenting as a post-auricular salivary fistula (Ann Med Health Sci Res 2014;4:136)
  • 22 year old woman with type I first branchial cleft cyst masquerading as a parotid tumor (Natl J Maxillofac Surg 2014;5:84)
  • 32 year old woman with intrathyroidal branchial cleft cyst (Korean J Radiol 2006;7:149)
  • 50 year old woman with branchial cleft cyst (J Oral Maxillofac Pathol 2014;18:150)
  • Multiple branchial cleft-like cysts in Hashimoto thyroiditis (Am J Surg Pathol 1989;13:45)
  • Treatment
  • Complete surgical excision of cyst and associated tract after clearing infection
  • Endoscopic cauterization via pyriform sinus for fourth branchial cleft cysts
  • Clinical Images
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    Fistula opening (1st branchial cleft anomaly)

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    First branchial cleft fistula opening

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    Bilateral fistula opening

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    Saliva coming out, third branchial fistula

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    Fistula opening above sternocleidomastoid muscle

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    Sinus originating from pyriform sinus

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    With cervical abscess

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    Fistulous tract in right pyriform sinus

    Radiology
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    Cystic lesion in left parotid gland

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    CT fistulogram

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    Fluoroscopic fistulogram

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    Cystic lesion in left parotid region

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    CT fistulogram

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    Infrahyoid cyst

    Gross Images
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    Fistula tract

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    Fistula tract ending in parotid gland

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    Collaural fistula

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    Third branchial fistula

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    Fistula tract exiting pharynx

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    Fourth branchial fistula

    Micro Description
  • Stratified squamous or ciliated columnar epithelium lining (Am J Pathol 1967;50:765, APMIS 1997;105:623)
  • Fibrotic wall with lymphoid follicles resembling lymph node or tonsil
  • May be secondarily infected
  • Cysts may have sebaceous or mucinous glands
  • Occasionally found in thyroid tissue as heterotopic cartilage, thymus or solid cell nests representing ultimobranchial body remnants
  • Micro Images
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    Cyst lined by stratified squamous epithelium

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    Cyst wall with lymphoid tissue

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    Sinus tract in parotid gland

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    Cyst wall with chronic inflammation

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    Fibrotic wall of a cyst

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    Lymphoid aggregates in cyst wall

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    Ciliated pseudostratified columnar epithelium

    Virtual Slides
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    Branchial cleft cyst

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    Branchial sinus

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    Branchial cyst

    Cytology Description
  • Squamous epithelial cells of variable maturity, abundant lymphocytes, macrophages, background of amorphous debris - these features are non-specific (Acta Dermatovenerol Alp Pannonica Adriat 2006;15:85, Eurocytology)
  • May be interpreted as suspicious for carcinoma (Cytopathology 2007;18:184)
  • Cytology Images
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    Squamous cells, keratin debris

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    High power

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    Pap stain

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    Inflammation

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    Cholesterol crystals

    Differential Diagnosis
  • First branchial cleft cyst: epidermoid cyst, dermoid cyst, cystic sebaceous lymphadenoma
  • Second branchial cleft cyst: lateral thyroglossal duct cyst
  • Third branchial cleft cyst: papillary carcinoma with cystic change (positive for TTF1, thyroglobulin)
  • Fourth branchial cleft cyst: thymic cyst