Subacute lymphocytic thyroiditis after lobectomy in a patient with papillary thyroid carcinoma: a case report

INTRODUCTION: Subacute lymphocytic thyroiditis is anautoimmune thyroid disease presenting with transient thyrotoxicosis as well as transient hypothyroidism. Several factors have been thought to be the initiating event in subacute lymphocytic thyroiditis. However, subacute lymphocytic thyroiditis that develops after thyroid lobectomy has not yet been reported in the literature. We report a case of subacute lymphocytic thyroiditis after lobectomy in a patient with papillary thyroid carcinoma. CASE PRESENTATION: A 30-year-old Korean woman was referred to our center for thyroid tumor operation. She was diagnosed with suspicious papillary thyroid carcinoma by fine needle aspiration at a local medical clinic. The thyroid ultrasonography demonstrated a diffusely enlarged thyroid gland with a 0.4×0.3cm sized hypoechoic nodule in the left lobe. Left thyroid lobectomy by endoscopic thyroidectomy was performed via a transaxillary approach, and the nodule was confirmed to be a papillary thyroid carcinoma. On postoperative day 1, a thyroid function test revealed hyperthyroidism, and on postoperative day 8, a thyroid function test again revealed hyperthyroidism with decreased radioactive iodine uptake. Thyroid function tests showed euthyroid on postoperative day 48 and hypothyroidism on postoperative day 86. She was treated with levothyroxine. CONCLUSION: Subacute lymphocytic thyroiditis can develop after thyroid lobectomy. Thyroid autoantigen released during thyroid lobectomy may cause the onset or exacerbation of the destructive process.