ABSTRACT
Around 50% of the population harbour thyroid nodules on ultrasonography, up to 7% of which may be malignant irrespective of size. While fine-needle aspiration biopsy is reliable, subjecting every thyroid nodule to this procedure is not cost-effective. Hence, ultrasonography is used primarily to characterise thyroid nodules, whereas nodules that have suspicious features are subject to a fine-needle aspiration biopsy. The presence of microcalcifications, macrocalcifications, irregular margins, 'taller-than-wide' shape, marked hypoechogenicity and intrinsic vascularity are features that render a thyroid nodule suspicious for malignancy. Spongiform appearance and the presence of colloid plugs or purely cystic nodules are considered features of benignity. In this article, these aforementioned sonographic features of malignancy and benignity are pictorially illustrated and a basic approach to dealing with solitary and multiple thyroid nodules is highlighted.