Thyroglossal cyst


· Epithelial remnant of tract from descent of thyroid
- thyroid descends from foramen caecum (2/3 toward back of tongue in midline; inverted V) to resting position in front of thyroid cartilage.

— hypertrophies and secretes mucoid fluid

— Lining columnar or squamous ± thyroid tissue.

Clinical

· Occurs from foramen caecum to sternum.

— 75% @ or just below hyoid

— 15% @ level of thyroid cartilage

· Midline 90%

— L of midline 10%

· Usually presents in childhood

— Mean age 5yrs

· Symptoms

— Lump

— moves on swallowing and on tongue protrusion

— Transilluminates

· Complications

— Infection

— Rupture or trauma ’ sinus

— Cancer (tends to be papillary)

Investigations

— FNA

— USS to confirm presence of normal thyroid

Treatment

· 25% recurrence if cystectomy alone, 5% if hyoid also taken (Mastery p385)

 

Sistrunk operation

· Transverse incision over cyst through platysma

· Raise sub-platysmal flaps

· Dissect cyst free from below, leave attachment to hyoid

· Divide straps from mid hyoid

· pass right angle around hyoid, divide mylohyoid and geniohyoid from mid hyoid

· divide centre 1-1.5cm of hyoid

· follow duct remnant up (can assist by depressing base of tongue) suture ligate as high as possible.

 

Thyroglossal sinus

· persistence of tract or bursting of cyst

 

What is the incidence of thyroglossal duct cyst

most common congenital cervical abnormalities (3x more common than branchial cleft remnants)

males=females

most present in childhood

What are the clinical features of thyroglossal duct cyst

anywhere from submental to suprasternal notch; usually located just below the hyoid

usually the track passed within or posterior to the hyloid bone

midline

rises with swallowing or protrusion of the tongue

lined by pseudostratified ciliated columnar epithelium, squamous epithelium, or

both, ± thyroid remnants in wall
- may contain only thyroid tissue in the body.

What is the management of a thyroglossal duct cyst

USS to confirm normal thyroid present (DDx ectopic thyroid)

Sistrunk procedure

transoral marsupialization or excision for a lingual TDC

What is the incidence of malignant change in thyroglossal duct

cysts

1%

papillary ca most common

also Hurtle cell, squamous and anaplastic ca

requires total thyroidectomy (may be metastatic) and iodine ablation

 

Lingual thyroid

· Failure of decent F>M,

· can cause local symptoms eg stridor

· Can be (often?) only thyroid tissue present.

· Ca risk higher than normal

But no MCT as no C-cells

· Rx: Decrease size with T4 . I131 ’ surgery