FNAB is the most important diagnostic tool in evaluating thyroid nodules and should be the first intervention. The technique is inexpensive and easy to perform, and it causes few complications. The four results of FNAB are benign disease, malignant disease, indeterminate for diagnosis, and nondiagnostic. Papillary thyroid carcinomas and medullary thyroid carcinomas are often positively identified on the basis of FNAB results alone.
The American Thyroid Association suggests that ultrasonography remains the most important imaging modality in the evaluation of thyroid cancer and should be used routinely to assess the primary tumor and all associated cervical lymph node basins preoperatively; positive lymph nodes may be distinguished from normal nodes on the basis of size, shape, echogenicity, hypervascularity, loss of hilar architecture, and presence of calcifications. Ultrasonography may also be useful in guiding FNAB of suspicious lymph nodes.
CT and MRI can be used to evaluate soft-tissue extension of large or suspicious thyroid masses into the neck, trachea, or esophagus and to assess metastases to the cervical lymph nodes. These studies do not have a role in the routine management of solitary thyroid nodules.
Serum TSH concentration is a highly sensitive measure for hyperthyroidism or hypothyroidism. A sensitive TSH assay is useful in the evaluation of solitary thyroid nodules. A low serum TSH value suggests an autonomously functioning nodule, which typically is benign. However, malignant disease cannot be ruled out on the basis of low or high TSH levels. Other thyroid function tests are usually not necessary in the initial workup. Serum thyroglobulin measurements are not helpful diagnostically because they are elevated in most benign thyroid conditions. Elevated serum calcitonin levels are highly suggestive of medullary thyroid carcinomas.
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Cite this: Elwyn C. Cabebe. Fast Five Quiz: Thyroid Cancer Practice Essentials - Medscape - Oct 01, 2020.