Thyroid Nodules – Tests And Diagnosis

Thyroid Nodules

Thyroid nodules are common. 4-7% of adults have such palpable formations and 50-70% of adults discover thyroid nodules after a ultrasound examination of the thyroid.

The risk for a thyroid nodule to be malignant is between 20-40%. Patients who presented a thyroid nodule that has grown over several months, those who presented pain in the thyroid nodule with an acute onset (usually due to a intracystic bleeding), the association between cervical lymph nodes and  insidious and persistent pain should be directed to an endocrinologist.

All patients with thyroid nodules that associates stridor, must present themselves on the same day for assessment by a specialist, because such events may be due to recurrent laryngeal nerve damage, secondary to a thyroid carcinoma.

Suspicious Symptoms In Patients With Thyroid Nodules

• A family history of thyroid cancer.
• History of radiation or exposure to ionizing radiation.
• Children who have thyroid nodules.
• Hoarseness or stridor without further explanations, which are associated with the presence of goiter.
• A thyroid mass  which is rapidly growing within the order of weeks.
• Palpable cervical lymphadenopathy.
• Insidious and persistent pain that lasts several weeks.

Initial investigations

All patients with thyroid nodules should perform a thyroid function tests. Patients with polinodular goiter associated with hyperthyroidism, have a lower risk of developing thyroid cancer.

Thyroid Nodules

Some studies have shown that subjects with high levels of TSH hormone, have an increased risk for thyroid malignancy.

Ultrasound examination

Can provide valuable information on thyroid node characteristics, the potential for malignancy and accurate assessment of growth by serial ultrasound examinations. American Thyroid Association recommends that all patients should benefit from ultrasound examination, while the guidelines issued by the British Thyroid Association suggest that this examination is useful only as a guide to aspiration and to identify possible non-dominant nodules.

Suggestive ultrasound aspects for thyroid cancer:

• Hypoecogen aspect – moderate risk.
• Absent halo or edges which are difficult to distinguish – moderate risk.
• Blood flow at Doppler examination – moderate risk.
• Microcalcifications – high risk.

Fine needle aspiration

Cytological test accuracy varies, depending on the manner of the sampling and the interpretation of results by the cytopathologist. Studies have shown that non-diagnostic aspirates rate ranges between 15-30% and is higher for thyroid nodules smaller than 1 cm, compared with those over 1 cm. If two attempts of fine needle aspiration do not allow the formulation of diagnosis, biopsy is recommended (with or without ultrasound guidance).

It was also found that of all the tests for diagnosing thyroid malignancy, fine needle aspiration was more accurate than ultrasound examination.

Thyroid Nodules

Ultrasound guidance increases the accuracy of fine needle aspiration from 85% to 95% and may also be useful in order to select the most suspicious thyroid node to be biopsied for a multinodular thyroid.

In patients with multinodular goiter, the most suspicious node in terms of  ultrasound appearance, is elected to be biopsied. If none of the thyroid nodes are suspicious, is elected to be biopsied the node with the largest dimensions.

Other investigations

• Nuclear magnetic resonance.
• CT
• Determination of serum thyroglobulin is not very useful in the diagnosis
• Highlighting antithyroid antibodies (ATPO) may be relevant if is wanted to be excluded autoimmune thyroiditis.