Thyroid nodules are lumps or growths of abnormal thyroid tissue that develop within the gland. A gland enlarged by a nodule can be called a goitre and a gland containing multiple nodules, a multi-nodular goitre. Thyroid nodules can vary widely in size and appearance. Some may be so small that they are only noticeable with an ultrasound examination and others can be large enough to extend in the chest and compress surrounding structures. Nodules can range from being completely solid, to mixed solid / fluid or entirely fluid (called cystic).
Thyroid nodules are very common with around 50% of people around the age of 60 having one. It is therefore not surprising that anywhere between 15% to upwards of 60% of medical imaging around the neck undertaken for other reasons will also find an incidental thyroid nodule. Evidence suggests that more than 6% of women and 1.5% of men have a noticeable nodule (one that is causing symptoms or can be seen or felt). The vast majority of nodules (more than 90%) are benign (non-cancerous).
The key investigation to assess the risk of a nodule being cancerous is ultrasound. An expert in ultrasound imaging (normally a consultant radiologist or sonographer) is able to grade nodules and decide which are most likely to be benign (and do not require follow up) and which might require further assessment such as needle testing (fine needle aspiration) and / or follow up scans.
