Branchial Cleft Cysts


1st branchial cleft cysts
--Occur between EAC and angle of the mandible
--these are NOT preauricular cysts or pits which are related to fusion of the Hillocks
--Type 1 are duplications of the EAC and often have skin or attachments to EAC or TM.  These are ectoderm only and run lateral to the facial nerve
--Type 2 contain mesoderm and ectoderm and can run deep to the facial nerve.  These often contain cartilage

2nd branchial cleft cysts
-2nd branchial cleft cysts are the most common (95% of all branchial cleft cysts)
- These lie anterior to the border of the SCM - they course lateral to the carotid and enter the pharynx at the tonsillar fossa

3rd branchial cleft cysts - rare
-Runs Deep to carotid, pierces thyrohyoid membrane with the superior laryngeal nerve and enters the pharynx at the pyriform sinus. 
-Thymopharyngeal cysts are 3rd cleft remnants

4th branchial cleft cysts - very rare
-Course depends on side: on Left (Left is more common) they course into the mediastinum around the ligamentum arteriosum.  On the Right they travel around the subclavian.  They ascend deep to carotid and can involve the thyroid gland.  They enter through the pyriform sinus or cricothyroid membrane.  Excision often requires removal of part of the thyroid.  They manifest as recurrent suppurative thyroiditis.