To Cut or Not to Cut? Evaluating Surgical Criteria for Benign & Nondiagnostic Thyroid Nodules

Serologic Evaluation
If a thyroid nodule is suspected on exam or found on imaging, assessment of thyroid function, via thyroid-stimulating hormone (TSH) measurement, is the recommended first step. If TSH is elevated, further evaluation for hypothyroidism is recommended, with testing for free thyroxine (T4) and antithyroid peroxidase (TPO) antibodies.⁴ If TSH is suppressed, further evaluation with free T4 and assessment for underlying causes of hyperthyroidism are indicated, including work-up for toxic nodular goiter.

Routine monitoring of serum calcitonin level is not recommended. However, if there is suspicion for medullary thyroid cancer—based on either US findings or family history—serologic screening for abnormal calcitonin level may be indicated.^4,5

Felicia’s lab results include a TSH of 1.30 µIU/mL (reference range, 0.30-3.00 µIU/mL). Based on this finding, what (if any) further serologic testing is recommended? None: With normal TSH and no concerning family or personal history, additional laboratory evaluation is not indicated.

Imaging a Thyroid Nodule
Thyroid US is the most sensitive imaging study for evaluating thyroid nodule characteristics. Thyroid uptake and scan is not indicated unless TSH is suppressed and evaluation for toxic nodular goiter is needed. Additional imaging studies, such as CT or MRI, are not recommended for thyroid nodule evaluation.

Based on the thyroid US, what characteristics of Felicia’s nodule are suggestive of a benign nodule? Of a malignant nodule? (See Table 2.)

FNA of the left-sided dominant nodule is indicated, based on the US findings of a partially solid component and size > 1 cm. Unfortunately, FNA is nondiagnostic, because it yielded cystic fluid only with scant follicular cells for evaluation.

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