Thirteen Cases of Autonomously Functioning Thyroid Nodule

Abstract

Autonomously functioning thyroid nodule (AFTN) is a condition where the thyroid nodules autonomously secretes thyroid hormone in a TSH-independent manner. In the present study, we reviewed the data of 13 patients with AFTN; the patients comprised 3 male and 10 female patients with a mean age of 62.6 ± 18.5 years (age range, 33–86 years) who had undergone surgery at the study center between 2012 and 2021; we collected data on the tumor volume, preoperative and postoperative serum FT3, FT4, and TSH levels, reason for consultation, and postoperative complications. The most common reasons for consultation were symptoms of thyrotoxicosis, such as tachycardia and atrial fibrillation, and presence of a cervical mass. A significant correlation was found between the volume of the functional nodules and the preoperative serum FT3 and FT4 levels, which were above the reference values in all the patients. The serum FT3 and FT4 levels decreased quickly to their respective normal ranges in all the patients following resection of the nodules, and those who were taking antithyroid medications were able to stop the medications from postoperative day 1. Although malignant transformation of AFTNs is considered rare, the finding of papillary carcinoma on postoperative histopathology in one case suggests the importance of always bearing in mind the possibility of malignancy when examining functional nodules, similar to the case with other types of nodules.

Other treatment options for AFTNs include medical therapy and ablation therapy, but these generally require prolonged treatment over several months to years. In the present case series, we found no cases of recurrent laryngeal nerve palsy, one of the potential complications of surgery. Surgery is indicated in patients who can tolerate the surgery, because it offers a rapid therapeutic effect and the opportunity to make a histopathological diagnosis.