Endocrine · Year 2 · from Endocrine
Case 1: Thyroglossal Duct Cyst
Patient Demographics
- Age: 8 years
- Sex: Male
- Occupation: Student (3rd grade)
Chief Complaint
"There's a bump in the middle of my son's neck that moves when he swallows."
History of Present Illness
An 8-year-old boy is brought by his mother who noticed a painless midline neck mass about 3 weeks ago. The mass has been slowly enlarging. The child denies pain, difficulty swallowing, or voice changes. He has had no fever or recent upper respiratory infections. The mass appears to move upward when he swallows or sticks out his tongue. There is no family history of thyroid disease.
Physical Examination
- Vital Signs: Normal for age
- General: Well-appearing boy in no distress
- Neck:
- 2 cm smooth, round, non-tender mass in anterior midline
- Located between the hyoid bone and thyroid cartilage
- Mass elevates with swallowing and tongue protrusion (positive Sistrunk sign)
- No overlying skin changes
- Thyroid gland palpable in normal position
- Lymph nodes: No cervical lymphadenopathy
Workup
- Laboratory Studies:
- TSH: 2.1 mIU/L (normal)
- Free T4: 1.2 ng/dL (normal)
- Ultrasound Neck:
- 2.2 cm anechoic (cystic) midline mass
- Located inferior to hyoid bone
- Normal thyroid gland in expected location
- Thyroid Scan (if concern for ectopic thyroid): Not needed in this case as normal thyroid identified on ultrasound
Diagnosis
Thyroglossal duct cyst
Treatment
- Sistrunk procedure:
- Surgical excision of the cyst
- Includes excision of the central portion of the hyoid bone
- Removal of tissue along the tract up to the foramen cecum (base of tongue)
- Rationale: Complete tract removal reduces recurrence rate from 50% to <5%
- Post-operative: Monitor for wound complications, hypothyroidism (rare)
- If infected at presentation: Antibiotics first, then elective surgery after resolution
Clinical Pearl
The thyroglossal duct is the embryologic tract through which the thyroid gland descends from the foramen cecum at the base of the tongue to its final position in the anterior neck. Failure of this tract to obliterate leads to thyroglossal duct cyst, the most common congenital neck mass in children. The pathognomonic finding is elevation of the mass with tongue protrusion, which occurs because the tract connects to the base of the tongue. Before surgical removal, it is essential to confirm that a normal thyroid gland exists in the proper location, as the cyst may contain the only functioning thyroid tissue in rare cases (1-2%).
Clinical Image
Clinical photograph showing a midline neck mass in the typical location of a thyroglossal duct cyst.
Image Source: Wikimedia Commons - "Thyroglossal cyst" License: CC BY-SA 4.0 URL: https://commons.wikimedia.org/wiki/File:Thyroglossal_cyst.jpg