Pictoral Essay:
Congenital Anomalies of
the Branchial Apparatus
Authors
Institutions
Objectives:
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Understand Embryology of the branchial
apparatus and embryogenesis of its anomalies.
Understand various classifications of branchial
anomalies.
Recognize and interpret imaging findings
associated with anomalies of the branchial
apparatus.
Direct workup using various imaging modalities
used in evaluation of branchial anomalies.
Embryology of Branchial Apparatus
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4th week of gestation.
Six mesodermal arches
Branchial clefts –
ectodermally lined.
Pharygeal pouches –
endodermally lined.
CN and Aortic arch
accompany each
branchial arch.
Branchial Apparatus
Development of Branchial Apparatus
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1st Arch, Cleft, and
Pouch persist.
2nd Arch increases in
thickness and proliferates
caudally
2nd, 3rd, and 4th Cleft
form cervical sinus of
His.
Sinus of His lined by
ectoderm.
Further Differentiation
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1st Branchial cleft
becomes external
auditory canal
Cervical Sinus of His
obliterated
Pharyngeal pouches
develop into thymus,
parathyroid glands, and
ultimobranchial body,
then migrate to their
final position.
Branchial Derivatives
Embryogenesis
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Vestigial remnants – resulting from
incomplete or failed obliteration of branchial
apparatus.
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Buried cell rests – cells are trapped in branchial
apparatus and form branchial cleft cysts later in
life.
Branchial Anomalies
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Sinus – incomplete tract,
opens externally
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Fistula – communicated
both externally and internally
from persistence of both
cleft and pouch.
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Cyst – no internal or
external comunication.
Radiographic Evaluation
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Begins with Ultrasound
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CT
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Non ionizing, non invasive.
Determines cystic vs. solid; size, and extent.
Color doppler – vascularity.
Morphologic characterization and staging.
Bone structures, calcifications, deep soft tissue anatomy
Low dose neck CT to avoid excess radiation.
MRI
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Multiplanar capability
Absence of ionizing radiation.
Superior contrast resolution and anatomic characterization of soft tissues.
Often requires sedation.
First Branchial Anomalies
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5-8 % of all defects.
Middle aged women.
1st Branchial structures:
maxilla, mandible,
eustacian tube, external
auditory canal, middle ear
structures.
Completed by 6-7 wks.
Can insinuate within
Parotid gland.
10 year old female presenting with
fistula.
Second Brancial Apparatus
Anomalies
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Vast majority (>95%) of
branchial anomalies.
¾ of anomalies are cysts.
Fistulas and sinuses present
earlier.
Passes between internal
and external carotid
arteries and ends near
tonsillar fossa.
External communication
with cervical sinus of His.
Four types of
nd
2
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Bailey type I:
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Classic location
Bailey type III:
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most superficial
Anterior surface SCM
Bailey type II:
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BCC
Extends medially
between ICA and ECA
bifurcation
Bailey type IV:
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Lies in pharyngeal
mucosal space.
41 year old male with neck mass.
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Bailey type II:
 most common.
 Remnant of
cervical sinus of
His.
Classic location:
 Anterior to SCM
 Lateral to carotid
space
 Posterior to
submandibular
gland.
10 mo. Child presented with neck
mass. Suspected abscess.
Third Branchial Apparatus
Anomalies.
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Very rare.
Requires careful anatomic
examination.
Pierces the thyrohyoid
membrane and enters
pyriform sinus
Posterior to carotid vessels
Anterior to Vegus nerve.
Posterior compartment
behind SCM.
Joins Cervical Sinus of His.
Child with Neck Fullness.
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Cystic mass in left
posterior
compartment
Beneath SCM.
Posterior to Carotid
vessels.
Fourth Branchial Apparatus
Anomalies.
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Very rare: complete fistula not
reported.
Origin at apex of pyriform
sinus, penetrates thyrohyoid
membrane.
Descends below aortic arch
Inferior to superior
lanryngeal nerve.
Superior to recurrent
laryngeal nerve.
Cervical sinus of His.
3 yo with recurrent neck abscess.
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Infected cyst anterior to carotid
artery
May communicate with pyriform
sinus or cervical sinus of His
Track descends below aortic
arch.
Case 1: Child with right facial
mass.
Submandibular
Gland
Carotid Sheath
Sternocleidomastoid
Case 2: Child with purulent
drainage from EAC.
Case 3: Child presenting with
neck mass.
Review
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Defects in branchial apparatus include
branchial, thymic, and parathyroid
anomalies.
Manifest as cysts, sinuses, fistulas, and
ectopic glands.
Embryogenesis: vestigial remnants from
incomplete obliteration or buried cell rests.
Radiography, US, CT, MRI used for
evaluation
Review
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Branchial Cleft Anomalies: Fistulae, cysts, sinuses.
Four types: Type II Branchial Cleft Cysts most
common.
Classic location BCC II: anterio-medial to SCM,
displacing submandibular glands anteriorly, lateral to
carotid vessels.
Types II – IV merge externally as Cervical sinus of
His.
Types III and IV are rare and require careful anatomic
examination for differentiation.
References
1. Benson MT, Dalen K, Mancuso AA, et al.: Congenital
abnormalities of the branchial apparatus: embryology and
pathologic anatomy. Radiographics 12:739-748, 1992.
2. Meuwly JY, Lepori D, Theumann N, et al.: Multimodality
Imaging Evaluation of the Pediatric Neck: Techniques and
Spectrum of Findings. Radiographics 25:931-948, 2005.
3. Koeller K, Alamo L, Adair C, Smirniotopoulos J.: Congenital
Cystic Masses of the Neck: Radiologic-Pathologic Correlation.
Radiographics 19:121-146, 1999.
4. Langman J. Medical Embryology 3rd Ed. Baltimore: Williams &
Wilkins, 1975; 234-236.
5. Barry H. The aortic arch derivatives in the human adult. Anat
Rec 1951; 111:221-238.