Cystic appearance of cervical lymph nodes is characteristic of metastatic papillary thyroid carcinoma

Purpose The usefulness of high‐resolution sonography in diagnosing cervical lymph node metastases from papillary thyroid carcinoma was investigated. The accuracy of a particular sign, cystic change within a node, in establishing the diagnosis was assessed. Methods The sonographic findings in 63 patients with enlarged cervical lymph nodes were retrospectively reviewed. The patients had undergone high‐resolution gray‐scale and color Doppler sonography followed by ultrasound‐guided fine‐needle aspiration (FNA) in all patients and surgical excision in 27 patients. Results Abnormal sonographic features were present in the lymph nodes of all 63 patients. In 14 (70%) of 20 patients with papillary thyroid carcinoma, sonography depicted cystic changes. This pattern was not found in any of the other 43 patients, in whom FNA revealed either metastasis from another malignancy (22 patients) or benign reactive lymphadenopathy (21 patients). Among the 63 patients, there were 43 true‐negative, 14 true‐positive, 6 false‐negative, and no false‐positive results in the diagnosis of metastatic papillary thyroid carcinoma using the presence or absence of an intranodal cystic area on sonography. These results yielded a 70% sensitivity, 100% specificity, 100% positive predictive value, 88% negative predictive value, and 90% overall accuracy for this criterion. Conclusions Cystic changes within a cervical lymph node are highly suggestive of metastatic papillary thyroid carcinoma. © 2002 Wiley Periodicals, Inc. J Clin Ultrasound 31:21–25, 2003