What a nodule is
A thyroid nodule is a lump within the thyroid gland, at the lower front of the neck. Nodules are common, and many are found by chance on an ultrasound scan done for another reason. Most are harmless. A small share are thyroid cancer, which is why a nodule is assessed and not left unexamined.
How a nodule is assessed
Three things are usually looked at: a blood test of thyroid function; an ultrasound scan of the neck, which shows the size of the nodule and how it looks; and, depending on that size and appearance, a sample of cells taken from the nodule with a fine needle and examined under a microscope (fine needle aspiration). Not every nodule needs a needle sample: small nodules that look harmless on ultrasound are usually followed with a repeat scan.
When an operation is discussed
An operation is usually discussed when:
- the needle sample shows thyroid cancer, or cells that are suspicious for it;
- the sample cannot settle the question even when repeated, and removing the half of the gland that holds the nodule is the way to a diagnosis;
- a large nodule or an enlarged gland (goitre) presses on the windpipe or the gullet and makes breathing or swallowing difficult;
- a nodule makes too much thyroid hormone, and this treatment is chosen over the alternatives;
- a nodule keeps growing during follow-up.
Whether half of the gland or the whole gland is removed depends on the findings, and is decided together with the endocrinologist.
When no operation is needed
Most nodules are watched: the ultrasound scan is repeated at intervals, and a needle sample is taken again only if the nodule changes. A new lump at the front of the neck, a lump that is getting bigger, or a hoarse voice that lasts more than three weeks should be examined.
This article gives general information; it does not replace an examination, a diagnosis or treatment.