Pre-surgical evaluation of suspicious thyroid nodules: diagnostic performance of neck ultrasonography for extrathyroidal extension.

  • Background: A preoperative neck ultrasound (US) is recommended for suspicious thyroid nodules, to guide the extent of surgery.

    Aim: To identify and evaluate the preoperative predictive value of US for ETE and to correlate US findings with pathological results.

    Materials and Methods: All patients referred to surgery for thyroid nodule Bethesda III-VI were prospectively enrolled. US signs of ETE were dynamically evaluated: Absent; Suspicious (nodule adjacent/budging to thyroid capsule without signs of capsular interruption; nodule with signs of capsular interruption; nodule invading surrounding soft tissue and/or perithyroidal muscles). Neck US results were compared with pathological findings. Pathological ETE was classified: Absent (intrathyroidal tumor/tumor with capsular invasion); Present (tumor with minimal ETE involving soft tissues; tumor with ETE invading surrounding perithyroidal muscles; tumor with gross ETE).

    Results: 109 patients (26 M, 83 F; median age 49.5 years, range 16-76) were enrolled. US ETE was absent in 25.7%. ETE was found on pathological examination in 33.9% of patients. The diagnostic performance of US for the evaluation of the presence of pathological ETE resulted in sensitivity of 86.5%, and NPV of 82.1%. Specificity was 31.9%, with a PPV of 39.5% (overall accuracy of 50.5%).

    Discussion & Conclusions: Ultrasonography is the ?rst-line imaging modality for patients with nodules submitted to surgery for suspected thyroid cancer. However, the US prediction of extrathyroidal invasion is poor, and probably inadequate – used alone –  for tailoring the subsequent surgical approach. Absence of suspicious US signs, on the other hand, has a substantial negative predictive value.

 

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