The management of thyroid nodules begins with a detailed ultrasound
examination to document the size and ultrasound features of the nodule and thereby
determine the risk malignancy. In hyperthyroid patients, a thyroid scintigram is
important as the great majority of hyperfunctioning thyroid nodules are benign.
Depending on the ultrasound pattern and size of the nodule, FNA biopsy may be
clinically indicated to exclude malignancy. A benign FNA biopsy completes the
diagnostic workup, however ongoing monitoring and repeat FNA biopsy may be
warranted in nodules displaying a high suspicion of malignancy on ultrasound. Nondiagnostic
nodules should undergo repeat FNA biopsy under ultrasound guidance and
if persistently non-diagnostic, management options include observation of very low to
low-suspicion nodules and thyroid surgery for nodules with an intermediate or high
suspicion pattern on ultrasound. Indeterminate nodules (Bethesda III, IV and V) require
further diagnostic workup and/or thyroidectomy. While Bethesda IV and V nodules are
primarily treated surgically, our approach is to repeat the FNA biopsy with/without
molecular testing for Bethesda III nodules and to consider ongoing observation or
thyroid surgery for persistently indeterminate nodules, depending on the sonographic
and cytological suspicion of malignancy. Cytologically malignant nodules are also
referred for thyroidectomy. The extent of thyroid surgery depends on the size of the
thyroid nodule, the patient’s clinical risk factors for thyroid malignancy, the risk of
extra-thyroidal extension and patient preference.
Keywords: Atypia of undetermined significance, Benign cytology, Bethesda
system for reporting thyroid cytopathology, Core-needle biopsy, FNA biopsy,
Follicular lesion of undetermined significance, Follicular neoplasm, Indeterminate
cytology, Non-diagnostic cytology, Suspicious for malignancy, Thyroid nodule,
Thyroid malignancy, Thyroid nodule molecular testing, Thyroidectomy, Thyroid
nodule growth, Thyroid nodule follow-up.
