Contrast-enhanced ultrasound combined with diagnostic nerve block for differentiating cervical sympathetic ganglion from metastatic lymph node: a case report.

Differentiating cervical sympathetic ganglion (CSG) from metastatic lymph nodes in the central neck compartment remains a diagnostic challenge, particularly in patients with thyroid carcinoma. Conventional imaging modalities, including contrast-enhanced computed tomography (CT) and ultrasound, may yield indeterminate findings due to overlapping morphological characteristics. We present a case with papillary thyroid microcarcinoma that was referred for thermal ablation. Preoperative CT suggested a suspicious level VI lymph node. Contrast-enhanced ultrasound (CEUS) combined with diagnostic ultrasound-guided nerve block for differentiating cervical sympathetic ganglion from metastatic lymph node was performed. The appearance of Horner syndrome after nerve block indicates that this lesion is a sympathetic ganglion.