Thyroid gland
Congenital anomalies
Branchial pouch / cleft anomalies

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

Revised: 16 February 2017, last major update August 2015

Copyright: (c) 2003-2017, PathologyOutlines.com, Inc.

PubMed Search: Branchial pouch thyroid

See also Lymphoepithelial cyst , Solid cell nests, Cystic ultimobranchial body remnants, Thymic tissue within thyroid gland, Parathyroid tissue within thyroid gland
Cite this page: Branchial pouch / cleft anomalies. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/thyroidbranchial.html. Accessed February 19th, 2017.
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
Sites
  • Sites of cysts:
    • First branchial cleft: preauricular area (type I cyst) or below the angle of mandible (type II), may be connected to external auditory canal; cysts are rarely malignant (Diagn Cytopathol 2008;36:876); 5% - 8%
    • Second branchial cleft: anterior to sternocleidomastoid muscle in midneck, may communicate with pharynx; 95% (Singapore Med J 2015;56:203)
    • Third / fourth branchial cleft (Pyriform sinus fistula): 2% - 5%
      • May be misdiagnosed as bronchogenic cyst
      • Usually left sided and associated with neck infection, treatment is ipsilateral thyroidectomy as lesions pass through thyroid
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)
Diagrams / Tables

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Branchial apparatus

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Branchial cleft anomalies location

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Anatomical relations

Clinical Features
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 Description
  • Ultrasound: low echogenic lesion with lack of internal septation
  • CT scan and MRI require sedation in children
Radiology Images

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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

Prognostic Factors
Case Reports
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

Gross Description
  • A smooth walled cyst with mucoid or watery contents, 2 - 6 cm in diameter (up to 10 cm in greatest dimension)
  • Infected / ruptured cyst may be obscured or obliterated by the fibroinflammatory reaction; the surrounding soft tissues may be densely fibrotic
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
  • Parathyroid glands, thymic tissue, tiny masses of cartilage and tiny glands lined by ciliated cells may be seen in normal thyroid glands, presumably related to anomalies of the development of the branchial pouches (J Anat 1976;122:77)
Micro Images

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Contributed by Dr. Andrey Bychkov:

PTC: cystic node mimics branchial cyst

Hashimoto thyroiditis with lymphoepithelial cyst



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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 cysts

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#103335, branchial sinus

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#98093, branchial cyst


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Case 10, right neck node

Cytology Description
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

Videos


Pharyngeal pouches
Differential Diagnosis