Is a thyroidectomy medically indicated for a 60-year-old male with a large substernal thyroid goiter (non-toxic single thyroid nodule) that is not suspicious for malignancy?

Thyroidectomy is Medically Indicated for Large Substernal Thyroid Goiter

Yes, thyroidectomy is medically indicated for this 60-year-old male with a large substernal thyroid goiter, even though it is not suspicious for malignancy. The presence of a substernal goiter itself constitutes an indication for surgical removal regardless of malignancy suspicion, based on natural history, compression risks, and lack of alternative effective treatments.

Primary Indications for Surgery in Substernal Goiter

The presence of a substernal goiter is an absolute indication for thyroidectomy, even in asymptomatic patients, because there is no other effective method of preventing progressive growth. 1

Natural History and Compression Risks

• Both primary and secondary substernal goiters exhibit slow but steady growth that inevitably leads to tracheal, esophageal, vascular, and neurologic compression syndromes 1
• Airway obstruction—a life-threatening emergency—can be suddenly precipitated by spontaneous or traumatic bleeding into the goiter or by tracheal infections 1
• This patient already demonstrates compression effects with a large anterior mediastinal mass and partial left vocal cord immobility, indicating progressive disease 1, 2

Malignancy Risk

• Substernal goiters carry a relatively high incidence of malignancy ranging from 7.4% to 12% in surgical series, despite not appearing suspicious on imaging 1, 2, 3
• The inability to adequately sample deep substernal components with FNA means occult malignancy cannot be reliably excluded 4
• Three patients in one series had occult malignancy discovered only after resection of goiters that underwent lobectomy alone 4

Imaging Confirms Surgical Indication

• CT scanning is superior to ultrasound for evaluating substernal extension and defining the degree of tracheal compression 5
• The documented large anterior mediastinal mass immediately inferior to the surgical bed confirms significant substernal extension requiring surgical planning 5, 1
• Cross-sectional imaging is essential for operative planning even when malignancy is not suspected 5

Surgical Approach and Timing

Surgical removal should be performed as soon as possible unless contraindications exist, because the natural history is progressive enlargement with increasing compression. 2

Recommended Procedure

• Transcervical substernal thyroidectomy (completion thyroidectomy of remaining left lobe) is the appropriate procedure 1, 2
• A cervical collar incision is adequate in 83-96% of substernal goiter cases 2, 3, 6
• Median sternotomy is rarely required (3-17% of cases) and typically reserved for primary intrathoracic goiters, recurrent goiters, or malignant disease 1, 3, 6

Surgical Outcomes

• When performed by experienced thyroid surgeons, perioperative mortality is practically zero 1, 3
• Transient recurrent laryngeal nerve injury occurs in 4-8.3% and permanent injury in 0-4% of cases 2, 6
• Transient hypoparathyroidism occurs in 8% and permanent hypoparathyroidism in 0-6% of patients 2, 3

Critical Pitfalls to Avoid

Do not delay surgery waiting for symptoms to worsen or for development of suspicious features. The risk of acute airway compromise, the inability to exclude malignancy without resection, and the progressive nature of substernal goiters all mandate timely intervention 1, 2.

Special Considerations in This Case

• The patient has already undergone left thyroidectomy with resultant partial left vocal cord immobility, increasing technical complexity 2
• Preoperative laryngoscopy has appropriately documented baseline vocal cord function before completion thyroidectomy 7
• The large size and substernal location make observation inappropriate despite benign imaging characteristics 1, 6

Aggressive surgical therapy for substernal goiters avoids life-threatening situations and results in minimal morbidity when performed by experienced surgeons. 1