solid nodule, high levels of irregular blood flow within the nodule or "taller-than-wide sign" (anterior-posterior diameter is greater than transverse diameter of a nodule). Features of benign lesion are: hyperechoic, having coarse, dysmorphic or curvilinear calcifications, comet tail artifact (reflection of a highly calcified object), absence of blood flow in the nodule, and presence of cystic (fluid-filled) nodule. However, the presence of solitary or multiple nodules is not a good predictor of malignancy. Malignancy is only diagnosed when ultrasound findings and FNAC report are suggestive of malignancy. The TI-RADS (Thyroid Imaging Reporting and Data Systems) are sonographic classification systems which describe the suspicious findings of thyroid nodules. It was first proposed by Horvath et al., based on the BI-RADS (Breast Imaging Reporting and Data System) concept. Several systems were subsequently proposed and adopted by international scientific societies. Their main aims are to characterize the risk of malignancy of nodules to better select nodules to submit to fine-needle aspiration cytology. Another imaging modality, which is ultrasound elastography, is also useful in diagnosing thyroid malignancy especially for follicular thyroid cancer. However, it is limited by the presence of adequate amount of normal tissue around the lesion, calcified shell around a nodule, cystic nodules, coalescent nodules. Fine needle biopsy Fine Needle Aspiration Cytology (FNAC) is a cheap, simple, and safe method in obtaining cytological specimens for diagnosis by using a needle and a syringe. The indications to do FNAC are: nodules more than 1 cm with two ultrasound criteria suggestive of malignancy, nodules of any size with extracapsular extension or lymph nodes enlargement with unknown source, any sizes of nodules with history of head and neck radiation, family history of thyroid carcinoma in two or more first degree relatives, multiple endocrine neoplasia type II, and increased calcitonin levels. However, increased calcitonin levels can also be attributable to smoking, chronic alcohol consumption, usage of proton pump inhibitors, and renal failure. The Bethesda System for Reporting Thyroid Cytopathology is the system used to report whether the thyroid cytological specimen is benign or malignant. It can be divided into six categories: Blood tests Blood tests may be done prior to or in lieu of a biopsy. The possibility of a nodule which secretes thyroid hormone (which is less likely to be cancer) or hypothyroidism is investigated by measuring thyroid stimulating hormone (TSH), and the thyroid hormones thyroxine (T4) and triiodothyronine (T3).Tests for serum thyroid autoantibodies are