Thyroid nodules are widespread in clinical practice. These commonly benign cellular lumps which develop from thyroid cells can be found in at least 50% of adults above the age of 60. Depending on their size and location thyroid nodules can be asymptomatic or cause symptoms such as shortness of breath or – in the case of hot nodules – hyperthyroidism (overactivity of the thyroid)
How are thyroid nodules discovered?
Often thyroid nodules are detected during a routine screening with visual ultrasound. Despite 50% of adults above the age of 60 having thyroid nodules, only about 4-7% of US adults do have a palpable lumps. It is therefore not unusual that patients are unaware of an existing, small and asymptomatic thyroid nodules. Only when the nodules becomes larger, causes symptomatic disease or starts to be visible and palpable, patients may notice the lump themselves.
Diagnosis of a thyroid nodule
For diagnosis and classification of a thyroid nodules various diagnostic tools can be used. First methods usually include a visual ultrasound of the front of the neck, palpation and a discussion about the medical history and symptoms of the patient. With those methods physicians get an overview of the size, location and symptoms caused by the nodule. At this stage it is also common to have a blood test for the evaluation of hormone levels, this can give an indication about the thyroid’s functioning.
As a second step the physician is likely to do more tests in order to classify the thyroid nodule and rule out malignancy. A scintigraphy (nuclear thyroid scan) is a commonly used diagnostic tool. This scan allows testing to establish if the thyroid is working properly or not. The test involves, the patient taking radioactive iodine. The iodine accumulates in those areas where hormone production is most prevalent.What are the risks?
The radioactive marker makes it possible to see if the nodule accumulates more radioactive iodine (hot nodule), less (cold nodule) or the same amount like any healthy tissue (indifferent nodule). Because hot nodules are almost never malignant, the physician may decide to discontinue further tests for hot nodules at this stage and recommend appropriate treatment. Cold and indifferent nodules, on the other hand, have a small risk of malignancy which is why further tests are likely to rule out malignant nodules. Physicians may use another type of scintigraphy, the so-called MIBI-scintigraphy to for further testing or decide to take a biopsy for tissue analysis prior to deciding about the possible treatment plan.