Ultrasonographic Sign of the Nonrecurrent Laryngeal Nerve

The nonrecurrent laryngeal nerve (NRLN) is a rare anomaly of the inferior laryngeal nerve and is associated with the aberrant subclavian artery (negative Y sign). Despite the low incidence, the risk of iatrogenic injury to the NRLN is high without awareness of this anomaly. Neck ultrasonography is an effective method for detecting vascular anomalies and lowering the risk of vocal cord paralysis. We reported a case of a 39-year-old female with a right thyroid nodule. Neck ultrasonography revealed one ill-defined and hypoechoic thyroid nodule with dimensions of 1.6 cm × 1.0 cm × 0.6 cm and a negative Y sign. The fine-needle aspiration cytology report showed suspicion of a follicular neoplasm, Hurthle cell type. After discussing with the patient, the right thyroid lobectomy was arranged. During the operation, the right NRLN was confirmed. No vocal cord paralysis was noted after the surgery. The patient was finally diagnosed with Hurthle cell adenoma.