Abstract

The thyroid nodule is a neoformation that occurs within the thyroid gland in about 1/3 of the population, usually with normal thyroid function. Females are more affected than males (4:1 ratio) in areas with sufficient iodine intake and increases in areas with mild or severe iodine deficiency. The most affected age ranges between 30 and 50 years old, but using the high-resolution ultrasound study its frequency reaches 20-68% of the population and age also decreases, affecting young people. Using a high-resolution ultrasound, the structure of the thyroid nodules can be solid (therefore made up of cells), mixed (partly liquid and partly solid), or completely liquid (cyst). The thyroid nodule can appear in a normal-sized gland or in a goiter; it can be single or multiple, unilateral or bilateral. Elastography exam can be added to improve the diagnosis.The causes of the appearance of a nodule can be familiar, related to the origin area (iodine deficiency), after external been radiations exposure (during pediatric or young age), or ionizing radiation or radioactive fallout, after a trauma in the neck region (hemorrhagic cyst), or from unknown causes. The most frequent diagnostic method for the detection of thyroid nodule is the high-resolution ultrasound with color doppler, which can be performed both for a specific reason, but also randomly for other organs evaluation (breast or neck vessels control). The nature of the thyroid nodule occurs with the fine needle aspiration (FNA) biopsy by ultrasound guide, with the subsequent cytological examination. The pathologist expresses the diagnostic opinion according to an international classification (Bethesda Classification System). For a more in-depth diagnosis, the new molecular biology methods can also be used searching for possible onco-gene modifications. The percentage of benign nodules is prevalent (90%) compared to thyroid carcinomas. Thyroid nodule therapy can only be follow-up or using thyroid hormone suppressive therapy (L-Thyroxine) or surgery. New therapies for nodules reduction, such as laser photocoagulation therapy, the use of radiofrequency and the high intensity focused ultrasound, have recently been introduced. Typically, these techniques are reserved for those patients with absolute or partially contraindications to surgery. The data published in the literature are encouraging, however other studies will be necessary to evaluate their concrete reliability and success in particular in large size nodules.

Keywords: Thyroid Nodule; Fine Needle Aspiration; Follicular Neoplasia; Bethesda Classification System; HIFU; RFA; L-Thyroxine Therapy

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