Thyroglossal Duct Cyst

• Most common congenital anomaly of the neck

• 2-4% of all neck masses

• Over half present in the first decade of life but may also be seen in adults
• Pyramidal lobe of the thyroid is the most common remnant of the thyroglossal tract (50% of population)
  
  
• Etiology

• Represents a persistent epithelial tract during the descent of the thyroid from the foramen cecum to its final position in the anterior neck
• Normally this duct obliterates early in fetal life

• Histologically

• Well-defined cyst with an epithelial lining composed of either squamous or respiratory epithelium
• There can sometimes be islands of thyroid tissue lying in the walls of the cysts
• Cysts are filled with mucoid or mucopurulent material, depending on whether the cyst has been infected

• Types of thyroglossal duct cysts

• Infrahyoid type
• 65% and is mostly found in the paramedian position
• Suprahyoid type
• Nearly 20% and is positioned in the midline
• Juxtahyoid cysts
• 15%
• Intralingual location
• 2%
• Suprasternal variety
• 10% of cases
• Intralaryngeal
• Very rare

• Clinical

• Nontender and mobile masses
• Infected cysts may manifest as tender masses with
• Dysphagia
• Dysphonia
• Draining sinus
• Fever
• Enlarging neck mass
• Often appear after an upper respiratory tract infection
• Airway obstruction possible, especially with intralingual cysts
• The pathognomonic sign is that the cyst moves with tongue protrusion

• Imaging

• Ultrasound and CT scanning are the radiologic tools of choice
• Ultrasound is the gold standard
• Ultrasound can distinguish between solid and cystic components
• CT scanning may reveal a well-circumscribed cystic lesion, 2-4 cm in diameter with capsular enhancement
• Thyroid scanning may be done to rule out the cyst containing the only functioning thyroid tissue

• Differential diagnosis

• Dermoid cyst
• Lymphadenopathy
• Sebaceous cysts
• Schwannomas
• Lymphatic malformations

• Complications

• Infection is probably the most common complication
• Local growth and invasion is extremely uncommon
• Carcinoma is extremely rare
• Occurs in about 1% to 2% of patients
• Thyroid ectopia
• Fewer than 5% of these cysts actually have ectopic thyroid tissue

• Treatment

• Surgical treatment of choice for thyroglossal cysts is the Sistrunk operation
• Includes dissection of the hyoid bone and the base of the tongue
• Recurrence is approximately 3-5% and is increased by incomplete excision and a history of recurrent infections
• Thyroid suppression therapy is done by many practitioners
• Recurrence is the most common complication and is managed with a central neck dissection

Thyroglossal duct cyst. Reconstructed CT scan of the neck demonstrates a midline cystic lesion (red arrow) with a slightly enhancing wall. The contents measured fluid density.
For the same photo without the arrows, click here

EMedicine - Congenital Malformations of the NeckTed L Tewfik, MD, FRCSC and Adi Yoskovitch, MD, MSc
Thyroglossal Duct Cyst- Lawrence M. Simon, M.D. Dept. of Otolaryngology-Head and Neck Surgery-Baylor