Aims: To evaluate the diagnostic accuracy of ultrasound (US) assessing the lateral compartment
lymph node metastasis in patients with primary papillary thyroid carcinoma (PTC), and to
demonstrate the incidence and patterns of the lateral lymph node metastasis.
Methods: We retrospectively reviewed 198 patients with primary PTC who underwent thyroidectomy
in addition to modified lateral neck dissections (MLND) involving level II to level V due to
clinically positive lateral neck disease. A skilled and experienced single operator performed all US
examinations. Surgical pathology results were accepted as the reference method and sensitivity,
specificity, and diagnostic accuracy of US in detecting metastatic lymph nodes established using
Results: In the study cohort, 10.1% of the patients had lateral compartment lymph node metastases
without any central compartment involvement. For the lateral compartment, 48.5% had level II,
74.7% had level III, 64.6% had level IV, and 29.3% of the patients had level V metastasis. None of
the patients had isolated level V metastasis. The sensitivity, specificity, and diagnostic accuracy of
US in identifying lateral lymph compartment metastasis ranged from 87% to 91.4%, 92% to 98.6%
92.4% to 96%, respectively. However, the sensitivity (74.7%) and diagnostic accuracy (76.2%) of
US significantly decreased for the central compartment while specificity (90%) remained similar.
Conclusion: US performed by a skilled operator has an excellent diagnostic accuracy for the
evaluation of lateral cervical lymph nodes in primary PTC; thus, might enable precise tailoring of
the management strategies. Moreover, the high incidence of level V involvement favors MLND
over selective approaches.