Crucial Sonographic Features of Extrathyroidal Extension - A Pictorial Review
Chia-Yi Lin, Singapore General Hospital
Background
Extrathyroidal extension (ETE), a feature associated with papillary thyroid carcinoma (PTC), describes the extension of the primary tumour beyond the thyroid capsule and its invasion into adjacent structures.
Among the suggested risk factors for patients with PTC, ETE has been identified as one with significant prognostic implications. This is attributed to its association with greater morbidity and mortality due to higher risk of incomplete surgical excision. Sonography is the first-line imaging modality for assessing thyroid nodules, and allows preoperative evaluation of ETE, which in turn facilitates surgical planning of thyroid cancers.