Lymphocytic thyroiditis on fine-needle aspiration biopsy of focal thyroid nodules: approach to management

OBJECTIVE. The purpose of this study was to determine the optimal management strategy for thyroid nodules diagnosed as lymphocytic thyroiditis on sonography-guided fine-needle aspiration biopsy (FNAB) of focal thyroid nodules. MATERIALS AND METHODS. One hundred eleven patients were included in this study: among 45 patients with follow-up sonography-guided FNAB, 21 underwent follow-up sonography more than 12 months after the initial sonography and 24 were followed up with sonography and sonography-guided FNAB within 12 months. Among 45 patients with follow-up sonography-guided FNAB, seven underwent thyroid surgery. Follow-up sonography results and cytopathologic results were used as reference standards. RESULTS. There were no malignancies among 71 probably benign lesions on initial sonography. In contrast, of the 40 lesions that were suspicious malignant on sonography, eight proved to be papillary thyroid carcinoma on follow-up sonography-guided FNAB and histopathology. CONCLUSION. Lymphocytic thyroiditis can show variable features on sonography. When a nodule shows probably benign features on sonography, follow-up with sonography is sufficient. However, if a nodule shows suspicious malignant features on sonography and shows no change or increase in size on follow-up examination, follow-up sonography-guided FNAB should be performed.