Thyroglossal Cyst

Question 1

How common are thyroglossal cysts?

Answer 1

• Most common cause of congenital neck swelling (53%)
• Found in 7% of the population
• Usually present in first decade of life
• Also sometimes seen in adults

Question 2

What are the different variants of thyroglossal cysts?

Answer 2

1. Infrahyoid - 26-65% in paramedian region
2. Suprahyoid - 20-25% in midline
3. Juxtahyoid - 15% close to hyoid bone
4. Intralingual - 2% in tongue
5. Suprasternal - <10%
6. Intralaryngeal - rare

Question 3

What is the pathophysiology of thyroglossal cyst?

Answer 3

Arise from a persistent thyroglossal duct which is formed when the thyroid descends from the foramen caecum to its final position in the midline of the neck

The duct can give rise to sinuses, fistulae or cysts

Symptoms arise from swelling itself or complications (e.g. infection)

Question 4

How do thyroglossal cysts present?

Answer 4

• Young patient <20yrs
• Fluctuant swelling in the midline of the neck along the line of thyroid descent
• Cyst moves upwards when PROTRUDING tongue - as it is attached to the thyroglossal tract which attaches to the larynx by the peritracheal fascia
• Non-tender - unless infected -> dysphagia, dysphonia, draining sinus, fever or increasing size
• Mobile
• Airway obstruction esp with intralingual cysts

Question 5

What are the differential diagnoses for a thyroglossal cyst?

Answer 5

• Skin and fascia =lipoma, sebaceous cyst
• Lymph nodes = infective, maligant reticuloses
• Lymphatics = cystic hygroma
• Vascular = carotid body tumour, carotid aneurysm, haemangiomas
• Salivary glands - submandibular gland tumour/sielectasis; parotid gland tumour in lower pole
• Pharynx = pharyngeal pouch
• Laryngomalacia
• Thymic sweling
• Thyroid swelling
• Branchial arch remnants = branchial cysts
• Sternomastoid tumours
• Cervical teratomas
• Dermoid cysts

Question 6

What investigations would you do for thyroglossal cysts?

Answer 6

TFTs - normal (excludes ectopic thyroid gland)

US - well-circumscribed, anechoic midline mass above the level of the thyroid; shows capsular enhancement

Other:

FNA - in all adults with TGC but only in children with suspicious features on USS.

Fistulogram - shows course of tract

Thyroid scanning - may show functioning ectopic thyroid

Barium swallow - if history of recurrent lateral neck abscess, in which a branchial cleft anomaly with a possible internal sinus opening is suspected

Direct laryngoscopy - if metastatic cervical neck cyst secondary to unknown primary SCC suspected

Question 7

What feature of thyroglossal cysts differentiates it from any other type of neck mass?

Answer 7

It moves up with protrusion of the tongue, as thyroid nodules should not move with tongue movement

Question 8

What is the management of thyroglossal cysts?

Answer 8

Surgical excision - prevents recurrent infection or missed cancer. Sistrunk procedure with incision at the hyoid. (shown)

OR Sclerotherapy - for non surgical candidates

Question 9

What are the complications of thyroglossal cysts?

Answer 9

• Ectopic thyroid - more common with TGCs
• Cancer within cyst
• Compressive symptoms
• Infection