Presentation on theme: "Pictoral Essay: Congenital Anomalies of the Branchial Apparatus"— Presentation transcript:
1Pictoral Essay: Congenital Anomalies of the Branchial Apparatus AuthorsInstitutions
2Objectives: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.
3Embryology of Branchial Apparatus 4th week of gestation.Six mesodermal archesBranchial clefts – ectodermally lined.Pharygeal pouches – endodermally lined.CN and Aortic arch accompany each branchial arch.
4Branchial ApparatusBy the end of 4th week of gestation, four well-defined pairs of branchial arches are visible externally; the fifth and sixth arches are small and cannot be seen on the embryonic surface.
5Development of Branchial Apparatus 1st Arch, Cleft, and Pouch persist.2nd Arch increases in thickness and proliferates caudally2nd, 3rd, and 4th Cleft form cervical sinus of His.Sinus of His lined by ectoderm.
6Further Differentiation 1st Branchial cleft becomes external auditory canalCervical Sinus of His obliteratedPharyngeal pouches develop into thymus, parathyroid glands, and ultimobranchial body, then migrate to their final position.
10EmbryogenesisVestigial remnants – resulting from incomplete or failed obliteration of branchial apparatus.Buried cell rests – cells are trapped in branchial apparatus and form branchial cleft cysts later in life.
11Branchial Anomalies Sinus – incomplete tract, opens externally Fistula – communicated both externally and internally from persistence of both cleft and pouch.Cyst – no internal or external comunication.Examples of a second branchial apparatus internal and external sinus tract. Second image is a complete third branchial apparatus fistula tract.
12Radiographic Evaluation Begins with UltrasoundNon ionizing, non invasive.Determines cystic vs. solid; size, and extent.Color doppler – vascularity.CTMorphologic characterization and staging.Bone structures, calcifications, deep soft tissue anatomyLow dose neck CT to avoid excess radiation.MRIMultiplanar capabilityAbsence of ionizing radiation.Superior contrast resolution and anatomic characterization of soft tissues.Often requires sedation.
13First Branchial Anomalies 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.From 6-8 weeks, the parotid gland forms from endoderm within the mouth and branches posteriorly toward the ear. At the same time, the facial nerve and muscle migrate anteriorly. Because the parotid gland and facial nerve have a somewhat later embryonic development, a vestigial first branchial anomaly can insinuate itself in a variable relation to the parotid gland or facial nerve.
15Second Brancial Apparatus Anomalies 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.
16Four types of 2nd BCC Bailey type I: Bailey type II: Bailey type III: most superficialAnterior surface SCMBailey type II:Classic locationBailey type III:Extends medially between ICA and ECA bifurcationBailey type IV:Lies in pharyngeal mucosal space.
1741 year old male with neck mass. Bailey type II:most common.Remnant of cervical sinus of His.Classic location:Anterior to SCMLateral to carotid spacePosterior to submandibular gland.
1810 mo. Child presented with neck mass. Suspected abscess.
19Third Branchial Apparatus Anomalies. Very rare.Requires careful anatomic examination.Pierces the thyrohyoid membrane and enters pyriform sinusPosterior to carotid vesselsAnterior to Vegus nerve.Posterior compartment behind SCM.Joins Cervical Sinus of His.
20Child with Neck Fullness. Cystic mass in left posterior compartmentBeneath SCM.Posterior to Carotid vessels.
21Fourth Branchial Apparatus Anomalies. Very rare: complete fistula not reported.Origin at apex of pyriform sinus, penetrates thyrohyoid membrane.Descends below aortic archInferior to superior lanryngeal nerve.Superior to recurrent laryngeal nerve.Cervical sinus of His.
223 yo with recurrent neck abscess. Infected cyst anterior to carotid arteryMay communicate with pyriform sinus or cervical sinus of HisTrack descends below aortic arch.Origin at pyriform sinus, descends below aortic arch, coarses in front of aorta in neck to cervical sinus of His.
23Case 1: Child with right facial mass. Submandibular GlandCarotid SheathSternocleidomastoid
27ReviewDefects 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
28Review 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.
29References1. Benson MT, Dalen K, Mancuso AA, et al.: Congenital abnormalities of the branchial apparatus: embryology and pathologic anatomy. Radiographics 12: , 1992.2. Meuwly JY, Lepori D, Theumann N, et al.: Multimodality Imaging Evaluation of the Pediatric Neck: Techniques and Spectrum of Findings. Radiographics 25: , 2005.3. Koeller K, Alamo L, Adair C, Smirniotopoulos J.: Congenital Cystic Masses of the Neck: Radiologic-Pathologic Correlation. Radiographics 19: , 1999.4. Langman J. Medical Embryology 3rd Ed. Baltimore: Williams & Wilkins, 1975;5. Barry H. The aortic arch derivatives in the human adult. Anat Rec 1951; 111: