Second branchial cleft cyst

A.Prof Frank Gaillard et al.

Second branchial cleft cysts are a cystic dilatation of the remnant of the 2nd branchial apparatus, and along with 2nd branchial fistulae and sinuses accounts for 95% of all branchial cleft anomalies.

Although a congenital abnormality, they tend to present in early adulthood (10-40 years of age) often after minor trauma or infection. Second branchial cleft sinus or fistulas, on the other hand, present earlier. Fistulas extend from the skin surface anterior to the middle of the sternocleidomastoid muscle, pass between the internal and external carotid arteries and eventually drain into the tonsillar fossa.

Typically, second branchial cleft cysts present as a rounded swelling just below the angle of mandible, anterior to sternocleidomastoid (although the position is variable - see classification below).

The cyst is typically filled with mucoid material, is well circumscribed and other than presenting as localised swelling, is asymptomatic. However, if infected, surrounding fat stranding and skin changes are evident.

Cysts can occur anywhere along the course of the second branchial apparatus, from the pharyngeal wall to the skin, as it passes laterally and inferiorly between the internal and external carotid arteries. The angle of the mandible is a common location.

  • sharply demarcated
  • posterior acoustic enhancement: 70% 3
  • imperceptible walls: 82%
  • echogenicity is variable 3
    • anechoic: 41%
    • homogeneously hypoechoic with internal debris: 24%
    • pseudo solid: 12%
    • heterogeneous: 23%
  • rounded or spheric, sharply circumscribed
  • fluid density centrally
  • thin wall
  • extension of the cyst wall between the ICA and ECA just above the carotid bifurcation (features sometimes referred to as the notch sign, tail sign or beak sign 6), long-established as pathognomonic, is still highly suggestive of the diagnosis; down-classification due to an example of Schwannoma mimicking a branchial cleft cyst in rarity section 7
  • T1: variable signal dependent on protein content
    • high protein content: high signal
    • low protein content: low signal
  • T2: usually high signal
  • T1 C+ (Gd): no enhancement in uncomplicated lesions
  • superimposed infection
Share article

Article information

rID: 806
Synonyms or Alternate Spellings:
  • 2nd branchial cleft cyst
  • Second branchial cleft cysts
  • 2nd branchial cleft cysts

Support Radiopaedia and see fewer ads

Cases and figures

  • Drag
    Case 1
    Drag here to reorder.
  • Drag
    Case 2: probable 2nd branchial cleft cyst
    Drag here to reorder.
  • Drag
    Case 3
    Drag here to reorder.
  • Drag
    Case 4: 2nd branchial cleft cyst
    Drag here to reorder.
  • Drag
    Case 5: atypical 2nd branchial cleft cyst (type IV)
    Drag here to reorder.
  • Drag
    Case 6: infected
    Drag here to reorder.
  • Drag
    Case 7: infected 2nd branchial cleft cyst and fistula tract secondary to left tonsilitis
    Drag here to reorder.
  • Drag
    Case 8: infected
    Drag here to reorder.
  • Drag
    Case 9: with a fistula
    Drag here to reorder.
  • Updating… Please wait.

    Alert accept

    Error Unable to process the form. Check for errors and try again.

    Alert accept Thank you for updating your details.