Is total or partial/unilateral thyroidectomy indicated for a patient with Hashimoto's thyroiditis and a left lobe nodule showing rare atypical follicular/oncocytic cells on ACR (American College of Radiology) TI-RADS (Thyroid Imaging, Reporting and Data System) histopathology?

Management of Thyroid Nodule with Atypical Follicular/Oncocytic Cells in Hashimoto's Thyroiditis

For a patient with Hashimoto's thyroiditis and a left lobe nodule showing rare atypical follicular/oncocytic cells on ACR TI-RADS histopathology, a total thyroidectomy is recommended rather than partial/unilateral thyroidectomy.

Rationale for Total Thyroidectomy

Risk Assessment

• The presence of atypical follicular/oncocytic cells in the background of Hashimoto's thyroiditis raises concern for potential malignancy
• Hashimoto's thyroiditis is associated with an increased risk of thyroid malignancy, particularly papillary thyroid carcinoma 1
• The oncocytic (Hürthle cell) variant of papillary thyroid carcinoma can occur in the setting of Hashimoto's thyroiditis 2

Guideline-Based Recommendations

• According to NCCN guidelines, total thyroidectomy is indicated when there are atypical cells, particularly in the context of autoimmune thyroid disease 3
• ESMO guidelines support total thyroidectomy for thyroid nodules with atypical features, especially when there is underlying thyroid disease such as Hashimoto's thyroiditis 3
• Total thyroidectomy allows for complete removal of all potentially affected tissue, reducing the risk of recurrence and need for reoperation 4

Benefits of Total Thyroidectomy in This Case

1. Comprehensive Management:

   • Eliminates the risk of occult malignancy in the contralateral lobe
   • Addresses the underlying Hashimoto's thyroiditis, which affects the entire gland
   • Provides definitive treatment for both conditions simultaneously

2. Diagnostic Advantages:

   • Allows complete histopathological examination of both lobes
   • Enables accurate staging if malignancy is confirmed
   • Facilitates postoperative monitoring with thyroglobulin as a tumor marker 3

3. Treatment Efficacy:

   • Reduces risk of recurrence if malignancy is present
   • Eliminates need for potential completion thyroidectomy later
   • Studies show that 53% of patients with Hashimoto's thyroiditis who undergo thyroidectomy have thyroid cancer at final histological examination, even when not suspected preoperatively 5

Considerations Against Partial Thyroidectomy

• Lobectomy alone may be insufficient when atypical cells are present in the context of Hashimoto's thyroiditis
• The risk of occult malignancy in the contralateral lobe is significant in patients with Hashimoto's thyroiditis 5
• If malignancy is confirmed after lobectomy, a second surgery (completion thyroidectomy) may be necessary, increasing overall surgical risk

Surgical Risks and Complications

• Total thyroidectomy can be performed with low risk of permanent complications in patients with Hashimoto's thyroiditis 5
• Potential complications include:
  • Transient hypocalcemia (32.1%)
  • Transient recurrent laryngeal nerve palsy (0.4%)
  • Postoperative neck hematoma (0.8%)
  • Permanent hypoparathyroidism (rare)
  • Permanent recurrent laryngeal nerve injury (rare)

Postoperative Management

• Thyroid hormone replacement therapy with levothyroxine will be required lifelong
• Regular monitoring of thyroid function tests to ensure adequate replacement
• If malignancy is confirmed, consideration for radioactive iodine ablation based on final pathology and risk stratification 3

Conclusion

Given the presence of atypical follicular/oncocytic cells in a patient with Hashimoto's thyroiditis, total thyroidectomy offers the most definitive diagnostic and therapeutic approach. This approach is supported by current guidelines and provides the best opportunity for comprehensive management of both the nodule with atypical cells and the underlying autoimmune thyroid disease.