Second Branchial Cleft Cyst

  • Etiology: remnant of embryonal branchial arch incompletely obliterated, courses from posterior to submandibular gland and anteromedial to sternocleidomastoid muscle and lateral to carotid space
  • Imaging: look between sternocleidomastoid muscle and submandibular gland
  • US: internal debris may look more solid
  • CT: low density, notch sign (cyst extension between internal carotid artery / external carotid artery bifurcation), if it has thick wall or contrast enhancement think infection
  • MRI: T1 hypointense, T2 hyperintense, no contrast enhancement
  • Clinical: 90% of branchial cleft cysts

Radiology Cases of Second Branchial Cleft Cyst

CT of second branchial cleft cyst
Axial (left) CT with contrast of the neck shows a round, low density mass on the right with rim enhancement anterior to the right sternocleidomastoid muscle and inferior to the angle of the mandible and posterior to the right submandibular gland that has a sinus tract to the skin best seen on the coronal CT (right).

Clinical Cases of Second Branchial Cleft Cyst

Clinical image of second branchial cleft sinus
Clinical images show a punctate cyst at the anterior border of the right sternocleidomastoid muscle (above) that with some massaging is seen to emit fluid (below).