The thyroid nodule--evaluation and management

Thyroid nodules are common; with the growing availability of sensitive TSH assays, fine needle aspiration biopsy (FNAB) and high resolution ultrasonography (HRUSG), thyroid nodules are being increasingly recognised, diagnosed and treated. The diagnosis of a thyroid nodule is associated with considerable anxiety for the patient; a systematic approach, by excluding the possibility of malignancy, helps allay such anxiety. Nodules are sometimes picked up on neck imaging for non-thyroid conditions; these so-called 'incidentalomas' also need evaluation to rule out malignancy. A sensitive TSH assay is usually the first investigation; a suppressed TSH level leading to a radionuclide scan and an FT4 level to detect toxic nodules that are best managed by radio-iodine or surgical ablation. Thyroid peroxidase antibody is estimated if the TSH level is high. Palpable nodules in euthyroid subjects are best evaluated by HRUSG followed by USG-guided FNA. For nodules <10 mm size, USG-guided FNA is recommended only if clinical or USG features are suspicious. While the benign nodules are kept under regular follow-up, all malignant nodules should be removed surgically. Cystic thyroid lesions are well managed by percutaneous ethanol ablation. Routine measurement of serum calcitonin and other sub cellular markers is not recommended.