Sandbox: wdx

Overview

Thyroid nodules are a common clinical problem, and differentiated thyroid cancer is becoming increasingly prevalent. The American Thyroid Association has published guidelines for the management of thyroid nodules, which were updated in 2015.

The major causes of thyroid nodule development include, multinodular (sporadic) goiter, Hashimoto's thyroiditis, cysts, macrofollicular/microfollicular adenomas, childhood radioiodine exposure, familial history, and gene mutations include N&H ras, RET, Gsp, C-MET (α and β subunit), TRK, EGF / EGF-R, and P53 mutation. Neck masses can be mistaken for thyroid nodules. The most important neck masses that can be mistaken with thyroid nodules include, thyroglossal duct cyst, parathyroid cancer, parathyroid cyst, and branchial cleft cyst. While the diagnosis of a thyroid nodule is established, thyroid nodule should be differentiated based on benign or malignant features and the type of nodule. Common risk factors associated with thyroid nodules include, older age, iodine deficiency, previous history of iodine deficiency and hypothyroidism, living in iodine deficient areas, family history of autoimmune diseases, multiparity, and smoking. A solitary thyroid nodule may become symptomatic if it grows rapidly due to hemorrhage or malignancies, invades laryngeal nerves, compressing nearby structures, and secretory nodules that produce TSH. Thyroid nodules may be a manifestation of thyroid cancer, that usually develops in the 6th decade of life, and start with symptoms such as weight loss, fatigue, and hoarseness. Without treatment, the patient with benignnodules may remain asymptomatic, while the patients with thyroid neoplasm may develop distant metastasis, which may eventually lead to death. The most common complications of thyroid nodules are hoarseness, horner syndrome, nodule rupture, needle track seeding, hemorrhage/hematoma, dysphagia, upper airway obstruction, pain, skin burn, vasovagal reaction, hypothyroidism, transient thyrotoxicosis, anaphylactic reaction, thromboembolism, and pneumothorax. Physical examination should focus on the thyroid gland and the lateral and central neck and should assess for supraclavicular and submandibular adenopathy. In case of active hot thyroid nodules that produce thyroid hormones, antithyroid drugs should be administered, that include beta-blockers, antithyroid drugs (methimazole,carbimazole,propylthiouracil), radioactive iodine, and thyroidectomy. If the nodule excision treatment (lobectomy, isthmectomy, and total thyroidectomy) is not curative, then treatment with postoperative radioactive iodine (RAI) remnant ablation and recombinant human TSH–mediated therapy is recommended. Surgical management of thyroid nodule is performed in case of non-diagnostic or suspicious biopsy, for removal of primary thyroid cancer or for thyroid cancer staging for radioactive ablation and serum thyroglobulin monitoring. Primary prevention of thyroid nodule is aimed at prevention of thyroid cancer. Avoidance of exposure to radiation and monitoring the population with an increased risk of development of a malignant thyroid nodule play major roles in primary prevention. Secondary prevention of thyroid nodules focuses on prevention of recurrence of nodules. Different prevention strategies may be used depending upon whether the nodule is benign or malignant. In case of a malignant nodule, the major focus is on the prevention of recurrence after removal of a primary nodule. Post-operative periodic monitoring with serum thyroglobulin levels, radioactive iodine scanning, neck ultrasound and thyroid stimulating hormone (TSH) may decrease the chances of recurrence.