Management of Lingual Thyroid
The management of lingual thyroid should primarily involve thyroid hormone suppression therapy as first-line treatment, with surgical excision reserved for cases with airway compromise, severe dysphagia, or ongoing hemorrhage.
Definition and Prevalence
- Lingual thyroid is an ectopic thyroid tissue located at the base of the tongue (junction of anterior two-thirds and posterior one-third)
- Results from arrested descent of the thyroid gland during embryogenesis
- Prevalence: approximately 1 in 3,000-10,000 people 1
- In 70% of cases, this is the only functioning thyroid tissue in the body 1
Clinical Presentation
Patients may present with various symptoms:
- Dysphagia (difficulty swallowing)
- Globus sensation (feeling of something stuck in throat)
- Upper airway obstruction
- Bleeding episodes
- Voice changes
- Neck mass
- Asymptomatic (incidental finding)
Diagnostic Evaluation
Laboratory Tests:
- Thyroid function tests (TSH, T3, T4) to assess functional status
- Many patients are hypothyroid due to insufficient thyroid tissue
Imaging Studies:
- Technetium-99m scintigraphy: confirms diagnosis and identifies if this is the only functioning thyroid tissue 2
- CT/MRI: evaluates size, extent, and relationship to surrounding structures
Management Algorithm
Step 1: Assess Thyroid Function
- Determine if the patient is euthyroid, hypothyroid, or hyperthyroid
- Check if other thyroid tissue exists elsewhere in the body
Step 2: Initial Management
- First-line treatment: Thyroid hormone suppression therapy 3
- Suppressive doses of thyroid hormone (levothyroxine)
- Goal: Suppress TSH to reduce size of lingual thyroid
- Monitor for clinical improvement of symptoms
Step 3: Surgical Management
Surgical intervention is indicated for:
- Airway compromise
- Severe dysphagia limiting oral intake
- Ongoing hemorrhage
- Suspicion of malignancy
- Failure of medical therapy
Surgical Approaches (when needed):
- Trans-cervical/Trans-hyoid approach: Most commonly used with good oncologic outcomes 4
- Transoral approach: For smaller lesions
- Lateral pharyngotomy
- Transoral robotic surgery (TORS): Emerging technique for less morbid excision 1
Special Considerations
Malignancy
- Malignant transformation is extremely rare
- If malignancy is confirmed:
- Complete surgical excision
- Consider radioactive iodine therapy post-surgery 1
Post-surgical Management
- Lifelong thyroid hormone replacement therapy is mandatory if no other functioning thyroid tissue exists 2
- Regular follow-up to monitor thyroid function
Potential Complications
- Post-surgical hypothyroidism
- Dysphagia
- Airway compromise requiring reintubation or tracheostomy (rare)
- Pharyngocutaneous fistula (rare, associated with mandibulotomy) 4
Monitoring
- Regular follow-up to assess symptom improvement
- Periodic thyroid function tests to ensure adequate hormone levels
- Monitor for potential complications
Pitfalls to Avoid
- Failure to recognize that lingual thyroid may be the only functioning thyroid tissue in the body
- Surgical removal without adequate preoperative assessment of thyroid function
- Inadequate hormone replacement therapy post-surgery