[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Radiology](https://durgical.com/en/radiology/) › [Ultrasound](https://durgical.com/en/radiology/areas/ultrasound/) › Thyroid nodules on ultrasound # Thyroid nodules on ultrasound - Finding An ultrasound of the neck shows what a thyroid lump is made of and its shape, which tells whether it needs a needle sample or just watching. Updated Nov 13, 2026 ## Key points - TSH first; a low TSH means scintigraphy, not FNA. - Suspicious: solid, markedly hypoechoic, taller-than-wide, irregular margin, microcalcifications. - Reassuring: purely cystic, spongiform, comet-tail artifacts. - Risk category plus size decides FNA or follow-up (TI-RADS idea). - Always look at the neck lymph nodes. ## What it is Thyroid nodules are very common: many adults have one on ultrasound, and almost all are benign. Ultrasound is the imaging test for every known or suspected nodule. It describes each nodule by five features: composition (cystic, spongiform, mixed or solid), echogenicity (brighter, the same or darker than normal thyroid, or darker than the neck muscles), shape (wider-than-tall or taller-than-wide on a transverse view), margin (smooth, lobulated, irregular or spreading outside the gland) and bright spots inside (echogenic foci such as comet-tail artifacts or microcalcifications). Risk-stratification systems such as TI-RADS combine these features into a category from benign to highly suspicious, and the category together with the nodule's size decides whether to sample it with fine-needle aspiration (FNA), follow it with repeat scans or leave it. The scan also checks the lymph nodes of the neck. Before any of this, a TSH tells whether the nodule may be hyperfunctioning. ## What it looks like - Reassuring: a purely cystic nodule, a spongiform nodule (many tiny cysts making up most of it) and comet-tail artifacts from colloid. - Suspicious: solid, markedly hypoechoic (darker than the strap muscles), taller-than-wide, irregular or infiltrative margin. - Microcalcifications (tiny bright dots without shadows) are a classic sign of papillary carcinoma. - Extrathyroidal extension, an interrupted rim calcification with soft tissue bulging through it, and suspicious neck nodes raise the risk sharply. - TI-RADS adds points for each feature to give a category; higher categories need FNA at a smaller size. - Abnormal neck node: round, lost fatty hilum, microcalcifications, cystic change or chaotic peripheral vessels. ## Why it looks that way - Malignant cells pack tightly with little colloid, so they reflect less sound and look darker than normal thyroid. - A taller-than-wide shape means the nodule grows across tissue planes rather than pushing them aside. - Colloid crystals cause the small comet-tail reverberation seen in benign colloid nodules. ## Differential and pitfalls - Diffuse thyroid disease can mimic nodules: Hashimoto thyroiditis gives a coarse, darker gland with pseudonodules. - Graves disease shows a diffusely enlarged gland with very increased flow on colour Doppler. - Large comet-tail artifacts are benign, but small bright dots without a tail may be microcalcifications: the radiologist decides. - A low TSH changes the path: a hot nodule on scintigraphy is rarely malignant and usually needs no FNA. - FNA cytology is reported with the Bethesda system (six categories), from non-diagnostic to malignant. ## Next step - Any thyroid nodule: request TSH first, then a thyroid and neck ultrasound reported with a risk category. - Low TSH: request thyroid scintigraphy; a hot nodule is treated as hyperfunctioning, not biopsied. - High-risk features above the size threshold, or a suspicious neck node: refer for ultrasound-guided FNA. - Low-risk nodule below the threshold: follow-up ultrasound at the interval the report suggests. - Rapid growth, hoarseness, a hard fixed mass or stridor: urgent referral to head and neck surgery or endocrinology. ## Test yourself Think of the answer, then tap the question to see it. ## Which ultrasound feature of a thyroid nodule is a classic sign of papillary carcinoma? Microcalcifications: tiny bright echogenic dots inside a solid hypoechoic nodule, without the comet tail of colloid. ## What is the first test for a newly found thyroid nodule? TSH. If it is low, a scintigraphy looks for a hot nodule, which rarely needs FNA; if it is normal or high, ultrasound guides FNA. ## What does a taller-than-wide shape on a transverse view mean? It is a suspicious feature: the nodule grows across tissue planes, which raises the probability of malignancy. ## Which nodule appearance is almost always benign? A purely cystic nodule or a spongiform nodule made up mostly of tiny cysts. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/radiology/thyroid-nodules-on-ultrasound/) ## Elsewhere in DurgiPedia - [Thyroid examination](https://durgical.com/en/clinical-exam/thyroid-examination/) ## Connections ## Related 4 - [Ultrasound: echogenicity, probes, Doppler and artefacts](https://durgical.com/en/radiology/ultrasound-echogenicity-probes-doppler-and-artefacts/) - [V/Q, bone and thyroid scans: when they are used](https://durgical.com/en/radiology/v-q-bone-and-thyroid-scans-when-they-are-used/) - [Interventional radiology: what it can do](https://durgical.com/en/radiology/interventional-radiology-what-it-can-do/) - [Choosing the right study: appropriateness and incidental findings](https://durgical.com/en/radiology/choosing-the-right-study-appropriateness-and-incidental-findings/) ## Related conditions 5 - [Thyroid nodule](https://durgical.com/en/conditions/thyroid-nodule/) - [Thyroid cancer (papillary)](https://durgical.com/en/conditions/thyroid-cancer/) - [Goitre](https://durgical.com/en/conditions/goitre/) - [Graves disease (hyperthyroidism)](https://durgical.com/en/conditions/graves-disease/) - [Thyroiditis (subacute, painless and postpartum)](https://durgical.com/en/conditions/thyroiditis/) [← All of radiology](https://durgical.com/en/radiology/) Educational content; it does not replace a radiologist's report and is not a clinical instruction. Each study is ordered on the patient's assessment and your institution's protocols. Sources: [Thyroid Nodule](https://www.ncbi.nlm.nih.gov/books/NBK535422/) (StatPearls (NCBI Bookshelf), 2023); [Thyroid Nodule Biopsy](https://www.ncbi.nlm.nih.gov/books/NBK557883/) (StatPearls (NCBI Bookshelf), 2023). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/radiology/thyroid-nodules-on-ultrasound/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/radiology/thyroid-nodules-on-ultrasound/