Right-Sided Thyroid Enlargement with Voice Changes and Cough on Palpation
Most Likely Diagnosis
This presentation is most consistent with a compressive multinodular goiter causing recurrent laryngeal nerve (RLN) compression or invasion, though malignancy (particularly anaplastic thyroid carcinoma) must be urgently excluded given the concerning features. 1, 2
The combination of muffled voice and cough elicited by palpation strongly suggests RLN involvement, which can occur through either direct compression by a benign goiter or invasion by malignancy. 1, 3
Critical Diagnostic Evaluation
Immediate Assessment Required
Perform direct laryngoscopy immediately to assess vocal fold mobility and identify RLN paralysis, as this is the primary diagnostic modality for evaluating voice changes and will guide all subsequent management. 1, 4
Fine needle aspiration cytology (FNAC) should be performed first before any imaging studies to rapidly categorize the mass as benign multinodular goiter versus carcinoma (papillary, medullary, or anaplastic). 2
Key Clinical Features to Assess
Evaluate for "woody firm fixed" thyroid texture, which is pathognomonic for anaplastic thyroid carcinoma and represents a medical emergency with near 100% disease-specific mortality. 2
Assess for dysphagia and dyspnea, as these compressive symptoms indicate significant mass effect on the esophagus and trachea, commonly seen with substernal extension. 5, 6, 7
Document the rapidity of symptom onset, as sudden growth suggests malignancy, while gradual progression over months to years favors benign goiter. 1, 8
Imaging Strategy
Once FNAC results are available, obtain CT scan of the neck and chest without contrast to evaluate:
- Degree of tracheal compression and deviation 5
- Substernal extension of the goiter 5, 6
- Retropharyngeal space involvement 5, 9
- Relationship to the recurrent laryngeal nerve 1
CT is superior to ultrasound for surgical planning because it better defines tracheal compression with less respiratory motion artifact and fully evaluates deep extension that ultrasound cannot assess. 5
If vocal fold paralysis is confirmed on laryngoscopy, imaging must extend from skull base to thoracic inlet/aortic arch to evaluate the entire course of the RLN, as unexplained vocal fold paralysis requires complete evaluation of the nerve pathway. 1
Differential Diagnosis Considerations
Benign Multinodular Goiter with Compression
- Most common cause of compressive neck symptoms 6, 7
- Can cause RLN compression without invasion, producing voice changes and cough reflex when palpated 3
- Typically gradual onset over years 8
Malignant Thyroid Neoplasm
- Anaplastic thyroid carcinoma presents with rapid growth, woody firm texture, hoarseness from RLN invasion, and dysphagia. 1, 2
- Papillary or follicular carcinoma with extrathyroidal extension can invade the RLN. 1
- Approximately 50% of anaplastic carcinomas arise from pre-existing differentiated thyroid cancer. 2
Critical Pitfalls to Avoid
Do not delay FNAC while waiting for imaging, as tissue diagnosis should precede cross-sectional imaging per American College of Radiology guidelines. 2
Do not assume benign disease based on hypothyroidism history, as approximately 50% of anaplastic carcinomas occur in patients with prior or coexisting differentiated thyroid carcinoma. 2
Do not perform imaging before laryngoscopy if voice changes are present, as vocal fold assessment is the primary diagnostic modality and will determine the extent of imaging needed. 1
Be aware that right-sided thyroid surgery carries risk of nonrecurrent laryngeal nerve (occurs in <1% of cases), particularly if CT shows retro-esophageal right subclavian artery. 1, 4
Urgent Surgical Considerations if Indicated
If large goiter with tracheal compression is confirmed, recognize that tracheomalacia may be present, and airway collapse can occur upon extubation after goiter removal, requiring careful anesthesia planning. 1, 5
Experienced surgical team is mandatory for large goiters, as RLN injury rates increase significantly with bulky disease, abnormal anatomy, and substernal extension. 1, 6, 7
Bilateral vocal fold paralysis represents a medical emergency requiring immediate airway management and possible tracheostomy. 4