Presentation on theme: "Dept. of Radiology, UNC Chapel Hill"— Presentation transcript:
1 Dept. of Radiology, UNC Chapel Hill Branchial Cleft CystsDavid M. Chaky, MDDept. of Radiology, UNC Chapel Hill
2 IntroductionThe embryologic model is used to explain the origins of all branchial apparatus anomalies.The most accepted theory proposes that vestigial remnants result from incomplete obliteration of the branchial apparatus or buried cell rests, and, thus, if cells are trapped in the branchial apparatus during the embryologic stage, they can form branchial cysts later in life.
3 The branchial apparatus consists of a series of 6 mesodermal arches separated from each other externally by ectodermal-lined branchial clefts (grooves) and internally by endodermal- lined pharyngeal pouches.By the end of the 4th week of gestation, 4 well-defined pairs of branchial arches are visible externally; the 5th and 6th arches are small and cannot be seen on the embryonic surface.
4 Embryology and Anatomy Branchial System: 6 pairs of pharyngeal arches separated by endodermally lined pouches and ectodermally lined clefts.Each arch consists of a nerve, artery, and cartilaginous structures.The remaining neck musculature gains contributions from cervical somites.
5 Common Lateral Neck Masses in Infancy Branchial cleft anomaliesLaryngocelesDermoid and Teratoid CystsSternocleidomastoid Pseudotumor of Infancy (fibromatosis colli)Plunging ranulasAdenopathy
6 First Branchial Cleft Cysts Imaging FindingsBest diagnostic clue: Cystic mass around pinna and EAC (type I) or extending from EAC to angle of mandible (type II)Well-circumscribed, non enhancing or rim-enhancing, low-density massIf infected, may have thick enhancing rim or be dense internallyTop Differential Diagnoses*Benign Lymphoepithelial Cysts*Venolymphatic Malformation (VLM)*Suppurative Adenopathy/Abscess*Nontuberculous Mycobacterial Adenitis
7 First Branchial Cleft Cysts Type IEctodermal Duplication anomaly of the EAC with squamous epithelium only.Parallel to the EACPretragal, post auricularConnection with TM or Malleus>IncusSurgical Excision
8 First Branchial Cleft Cysts Type IISquamous epithelium and other ectodermal componentsAnterior neck, superior to hyoid bone.Courses over the mandible and through the parotid in variable position to the Facial Nerve.Terminates near the EAC bony-cartilaginous junction.Surgical excision- superficial parotidectomy
10 First Branchial Cleft Cysts Accounts for 8% of all branchial apparatus remnantsMost common location for 1st BCC to terminate is in EAC between its cartilaginous & bony portions
11 Second Branchial Cleft Cysts Most Common (90%) branchial anomalyPainless, fluctuant mass in anterior triangleInferior-middle 2/3 junction of SCM, deep to platysma, lateral to IX, X, XII, between the internal and external carotid and terminate in the tonsillar fossaSurgical treatment may include tonsillectomy
12 Second Branchial Cleft Cysts Imaging FindingsLow density cyst with non enhancing wall & surrounding soft tissues, unless infectedIf infected, wall is thicker & enhances with surrounding soft tissues appearing "dirty" (cellulitis) or internally denseTop Differential DiagnosesLymphangiomaThymic cystSuppurative jugulodigastic nodeCystic vagal schwannomaCystic malignant adenopathy (ALWAYS CONSIDER THIS POSSIBILITY IN ADULTS!)
14 Second Branchial Cleft Cysts * Epidemiology: 2nd BCC account for > 90% of all branchial cleft anomalies in teens and adults, 66-75% in children* Most common signs/symptoms: Painless, compressible lateral neck mass in child or young adult* Neck mass often chronic, recurrent, increasing in size with upper respiratory tract infection* Beware an adult with first presentation of "2nd BCC”* Mass may be metastatic node from head & neck SCCa primary tumor
15 Third Branchial Cleft Cysts Rare (<2%)Similar external presentation to 2nd BCCInternal opening is at the pyriform sinus, then courses cephalad to the superior laryngeal nerve through the thyrohyoid membrane, medial to IX, lateral to X, XII, posterior to internal carotidSurgical approach must visualize recurrent layngeal nerves- Thyroidectomy incision