When a patient presents with an anterior neck swelling suspected to be a goitre, it should first be assessed as follows:
- Confirm whether the mass is intrathyroidal or extrathyroidal using clues from the history, physical examination, and imaging (ultrasound and/or CT).
- Assess cervical lymph nodes with an ultrasound when a thyroid nodule is being evaluated.
- If the lump arises from the thyroid gland, assess the functional status of the thyroid. The history, physical examination, and free T4 and TSH measurements are used.
- Rarely, when there are features suggestive of a malignant cause, further evaluation such as cytology may be required.
Most thyroid nodules are asymptomatic. However, one should look for symptoms of hypothyroidism or hyperthyroidism and for local compressive symptoms. .
Symptoms of hyperthyroidism include irritability, increased perspiration, heat intolerance, palpitations, tremors, anxiety, insomnia, fine brittle hair, frequent bowel movements, and weight loss.
Symptoms of hypothyroidism include cold intolerance, constipation, weight gain, fatigue, and dry and itchy skin.
Symptoms of local compression include dysphonia, dysphagia, and dyspnoea.
Look out for risk factors for malignancy:
- Male sex
- Age at presentation <20 years or >60 years
- History of rapid growth
- Previous head and neck irradiation
- Familial history of thyroid cancer or other endocrine malignancies such as MEN.
- Inspect and palpate the anterior and lateral aspects of the neck to assess for thyroid enlargement, presence of nodules, and cervical lymphadenopathy. Swallowing during palpation can improve the detection of nodules.
- Check for signs of hyperthyroidism: tachycardia, arrhythmias, muscle wasting, tremor, brisk reflexes, and friable hair.
- Check for signs of hypothyroidism: bradycardia, thickened and puffy appearance of skin (myxoedema), and delayed relaxation phase of reflexes.
- Visualisation of vocal fold movement is very helpful in dysphonic patients. This can be done with a dental mirror and a headlight, an ultrasound examination, or with a flexible nasopharyngoscope.
- Physical findings suggestive of malignancy include:
- Nodules >4 cm in size
- Firmness on palpation
- Fixation of the nodule to adjacent tissues
- Cervical lymphadenopathy
- Vocal cord paralysis.
Majority of goitre patients are euthyroid. This is most easily confirmed by a serum TSH level.
Low TSH needs further assessment with free T4 and T3 to confirm hyperthyroidism.
A diffusely enlarged goitre is suggestive of Graves’ disease or thyroiditis, and a radioactive iodine uptake and scan will typically differentiate between these conditions.
Abnrmally high TSH warrants further assessment for free T4 and autoantibodies.
Serum calcium (total and ionised) and intact parathyroid hormone levels may be assessed if there is a suspected enlarged parathyroid gland.
Cervical ultrasound may be used to assess impalpable nodules, and central or lateral neck lymphadenopathy.
Malignancy cannot be definitively diagnosed or excluded with ultrasonography. However, the presence of the ultrasonographic features consistent with malignancy may be an indication for FNA biopsy.
This should be performed in cases of supressed TSH levels, to identify autonomously hyperfunctioning (‘hot’) nodules and to distinguish between Graves’ disease and thyroiditis.
Computed tomography (CT) and magnetic resonance imaging (MRI)
These have no primary role in initial evaluation of a thyroid mass. However, they can be used for accurately assessing large substernal goitres, identifying lymph nodes that not visualised by ultrasound, large goitres with posterior extension and diffuse bulky lymphadenopathy.
Fine needle aspiration cytology (FNAC)
Ultrasound-guided FNAC is choicely used for evaluating suspicious thyroid nodules found on preceding ultrasound.
Diagnostic lobectomy should be considered for definitive histological diagnosis following two or more unsatisfactory or indeterminate FNA biopsies.