Branchial Cyst

Question 1

What is a branchial cyst?

Answer 1

A benign development defect of the branchial arches

Question 2

What is the cyst filled with?

Answer 2

Acellular fluid with cholesterol crystals and encapsulated by stratified squamous epithelium

Question 3

What can they enlarge following?

Answer 3

Respiratory tract infection

Question 4

What age do they typically present at?

Answer 4

Late childhood, early adulthood

Question 5

How do they typical present?

Answer 5

Asymptomatic lateral neck lumps, anterior to SCM

Question 6

What are the usual examination features?

Answer 6

Unilateral, typically on left 
Lateral, anterior to SCM
Slowly enlarging
Smooth, soft, fluctant
Non-tender
A fistula may be seen 
Non movement on swallowing 
No transillumination

Question 7

What differential diagnoses are there for a neck lump in children?

Answer 7

Congenital: branchial cyst, thyroglossal cyst, dermoid cyst, vascular malformation

Inflammatory: reactive lymphadenopathy, lymphadenitis

Neoplastic: lymphoma, thyroid tumour, salivary gland tumour

Question 8

How are they treated?

Answer 8

Conservative or surgical excision
With surgery, recurrence is common usually due to incomplete excision (often tracts of cyst pass near important structures e.g IJV, carotid artery, facial nerve - making complete excision high risk of complications)

Question 9

What causes a branchial cyst?

Answer 9

Failure of obliteration of one of the branchial clefts