Thyroglossal Cyst

Question 1

Define:

Answer 1

• An epithelium-lined fluid-filled sac found along the course of descent of the thyroid gland, resulting from incomplete closure of the thyroid’s migration path

Question 2

Aetiology:

Answer 2

• The thyroglossal duct is an embryonic remnant of the path of descent of the thyroid gland from the mouth down to its normal position during development
• The duct normally disappears in the 6th week, but if some tissue remains, it could develop into a cyst

Question 3

Risk factors:

Answer 3

o RARE familial variants

Question 4

Epidemiology:

Answer 4

• Presents in CHILDREN and ADOLESCENTS
• Mean age of presentation: 5 yrs
• 3 x more common than branchial cysts

Question 5

Symptoms:

Answer 5

• A swelling/lump is noticed in the midline of the anterior neck
• Usually ASYMPTOMATIC
• May be tenderness or rapid enlargement due to infection

Question 6

Signs:

Answer 6

• Midline, smooth, rounded swelling
• Typically found between the thyroid notch and the hyoid bone
• Moves upwards on protrusion of the tongue
• Moves upwards with swallowing
• Can be transilluminated – using a pen torch, a light in shone across the lump. A swelling containing clear fluid will glow, whereas solid mass will not.

Question 7

Dx:

Answer 7

o Lymph node
o Dermoid cyst
o Ectopic thyroid tissue
o Chondroma (benign cartilaginous mass) – bony hard
o If age >20, probably thyroid isthmus mass.

Question 8

Investigations:

Answer 8

• NONE may be necessary if the patient is euthyroid
• If the cyst is suprahyoid, TFTs should be performed to exclude a lingual thyroid - because removal of the lingual thyroid will make the patient hypothyroid
• Ultrasound/MRI
o Helps differentiate from other structures