Management of Thyroid Nodules

Abstract

Thyroid nodules are common and the prevalence varies between 4 and 7% by palpation and 19–68% by high-resolution USG. Most thyroid nodules are benign, and the malignancy rate varies between 7 and 15% of patients. Thyroid nodules are detected incidentally during clinical examination or, more often, during imaging studies performed for another reason. All detected thyroid nodules should be evaluated clinically. The main test in evaluating thyroid function is thyroid stimulating hormone (TSH). If the serum TSH level is below the normal reference range, a radionuclide thyroid scan should be performed to determine whether the nodule is hyperfunctioning. If the serum TSH level is normal or high, ultrasonography (US) should be performed to evaluate the nodule. US is the most sensitive imaging method in the evaluation of thyroid nodules. Computed tomography (CT) and magnetic resonance imaging are not routinely used in the initial evaluation of thyroid nodules. There are many risk classification systems according to the USG characteristics of thyroid nodules, and the most widely used in clinical practice are the American Thyroid Association guideline and the American College of Radiology Thyroid Imaging Reporting and Data System. Fine needle aspiration biopsy (FNAB) is the gold standard method in the evaluation of nodules with indication according to USG risk class. In the cytological evaluation of FNAB, the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) is the most frequently applied cytological classification. TBSRTC is a simplified, 6-category reporting system and was updated in 2023. The application of molecular tests to FNAB specimens, especially those diagnosed with Bethesda III and IV, is increasing to reduce the need for diagnostic surgery. Especially in Bethesda III and IV nodules, different methods are applied in the treatment of nodules according to the malignancy risk of each category, these are follow-up, surgical treatment, radioactive iodine treatment, and non-surgical ablation methods.

Autoimmune Thyroid Disease and Differentiated Thyroid Carcinoma: A Review of the Mechanisms That Explain an Intriguing and Exciting Relationship

“…In these “indeterminate” categories, management usually consists of strict follow-up without intervention, performing periodic cytological controls or in some cases, surgical management (lobectomy/thyroidectomy) [ 114 ].…”

Diagnostic models for predicting malignancy in thyroid nodules classified as Bethesda Category III in an endemic region

“…Recent studies in the literature show that non-surgical interventional procedures are increasing, especially in symptomatic benign thyroid nodules, thyroid cysts, and toxic nodules. 24 In addition to the methods used, a single FNAB is sufficient for autonomous nodules with low-risk ultrasound features or benign cytology. 25 Since the morphological characteristics of treated nodules may change, they should be monitored clinically and ultrasonographically.…”

A case report of renal cell carcinoma metastasis revealed through late‐onset thyroid nodules

“…Sonographically, metastatic RCC to the thyroid gland is characterized by solid or solid cystic, irregularly shaped nodules with heterogeneous echogenicity, with or without calcification. 14 Although ultrasound imaging alone may not provide definitive discrimination, fine needle aspiration with immunohistochemical (IHC) staining can help differentiate primary thyroid carcinoma from metastatic thyroid lesions, particularly in patients with a known history of malignancy. Additionally, PET scans are considered beneficial complementary tools for evaluating distant metastasis and guiding treatment planning.…”