Thyroid Nodule

About Thyroid Nodule

Thyroid nodules are very common, found in approximately 50 to 65 percent of adults on ultrasound, though most are asymptomatic and benign. Approximately 5 to 15 percent of thyroid nodules are malignant, usually papillary thyroid carcinoma. Risk factors for malignancy include female sex though male sex increases cancer risk within nodules, age under 20 or over 70, radiation exposure particularly in childhood, and family history of thyroid cancer. Most nodules are discovered incidentally on imaging performed for other reasons carotid ultrasound, CT neck, PET scan. Large nodules may cause compressive symptoms difficulty swallowing dysphagia, difficulty breathing when lying flat, voice changes if compressing the recurrent laryngeal nerve, or a visible neck mass. Painful nodules suggest hemorrhage into a cyst or thyroiditis. Evaluation begins with TSH. If TSH is suppressed, a radioactive iodine thyroid scan distinguishes autonomous hot nodules that rarely need biopsy from cold nodules. For nodules over 1 cm, thyroid ultrasound assesses features suspicious for malignancy microcalcifications, hypoechoic, taller than wide, irregular margins, extrathyroidal extension. Ultrasound guided fine needle aspiration FNA with the Bethesda System for reporting provides cytologic diagnosis. Bethesda categories range from I nondiagnostic to VI malignant. Molecular testing Afirma, ThyroSeq on indeterminate nodules helps guide surgery decisions. Treatment ranges from observation for benign nodules to thyroidectomy for malignant ones. Lobectomy may suffice for small low risk cancers. Active surveillance is increasingly used for microcarcinomas under 1 cm.