THE CONTEXT
Assessment proceeds from clinical evaluation to ultrasonography and selective cytology, with functional or cross-sectional imaging reserved for particular situations.
Initial clinical assessment
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Clinical history and examination remain the cornerstone of diagnosis. Radiation exposure and family history should be discussed.
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Examine the central neck and regional lymphatics, and assess vocal cord function.
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Consider biochemical assessment of thyroid function at the first encounter if it has not already been performed.
Ultrasonography and cytology
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Ultrasonography is the next step after initial assessment and is described as the most accurate non-invasive investigation for assessing thyroid swellings.
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Ultrasonography identifies the presence, size and number of nodules and helps estimate malignancy risk.
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Lesions are categorised as benign, indeterminate or malignant. Benign lesions require no further assessment unless surgery is being considered for compressive symptoms.
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Indeterminate or malignant lesions should undergo fine-needle aspiration cytology.
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Clinical, ultrasonographic and cytological assessment characterises most lesions as benign, malignant or indeterminate, guiding further treatment.
Functional imaging in thyrotoxicosis
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A thyrotoxic patient represents one of the few indications for a radio-iodine uptake scan, which assesses nodule function.
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Hot nodules are very rarely malignant. Cold nodules require assessment as for other thyroid neoplasms.
Imaging suspected extensive disease
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Consider contrast-enhanced imaging covering the neck and chest when there is widespread nodal disease or suspected locally invasive disease affecting the airway.
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This imaging assesses visceral invasion and is superior to ultrasonography for defining mediastinal and thoracic disease.
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The passage prioritises accurate preoperative assessment of disease extent over concerns that iodine-containing contrast may delay radioactive iodine therapy.