Hashimoto's thyroiditis is an autoimmune disease involving the thyroid gland that slowly leads to hypothyroidism. In some patients, Hashimoto's thyroiditis can lead to distinct nodule formation in the absence of true neoplasm. We reviewed the diagnostic approach and clinical outcome of thyroid surgery conducted on patients with Hashimoto's thyroiditis presenting as distinct thyroid nodules.

We performed a retrospective review of the medical records of patients who underwent thyroid surgery for thyroid nodules that showed no evidence of true neoplasm other than Hashimoto's thyroiditis in the final histopathologic diagnosis.

Between July 2003 and June 2007, 12 patients in whom the final pathologic diagnosis showed nodular Hashimoto's thyroiditis received a hemithyroidectomy. Six of these patients developed postoperative hypothyroidism. Preoperative fine needle aspiration (FNA) suggested the diagnosis of a benign nodule in 2 patients, follicular neoplasm in 2 patients, Hürthle cell neoplasm in 3 patients, and suspicious malignancies in 3 patients. Two patients had non-diagnostic FNA results. Thyroid scans revealed the presence of cold nodules in 4 out of 5 patients. However, thyroid ultrasonography showed features suggesting benign nodules in all 12 patients.

Because this study only included patients who underwent surgery, the diagnostic accuracy of each modality cannot be determined based on these results. However, the high incidence of postoperative hypothyroidism suggests that surgical decisions should be made with caution when dealing with patients with Hashimoto's thyroiditis. Additionally, the role of ultrasonography in these patients should be evaluated further.