Neck Lymph Nodes in Chronic Autoimmune Thyroiditis: The Sonographic Pattern

Background: Neck lymph nodes may be involved in the pathogenesis of chronic autoimmune thyroiditis (CAT). This study was undertaken to identify which of the sonographic features of cervical lymph nodes are readily applicable to patients affected by CAT compared to healthy control subjects. Methods: We recruited 106 patients (92 females and 14 males) with CAT and 70 control subjects (53 females and 17 males) without clinical, biochemical, and ultrasonographic evidence of thyroid and neck diseases. We performed laboratory tests (thyrotropin, antithyroperoxidase antibodies, antithyroglobulin antibodies, and ultrasonography) to evaluate in each group: (i) thyroid function, autoimmunity, and morphology; (ii) number, topographic distribution (levels I-VI), and morphology of neck nodes (long-axis diameter; short-axis diameter; short-axis/long-axis ratio; absence or presence of hilus). Results: Total number of neck nodes with long-axis diameter > 10mm was significantly higher in the CAT group than in the control group (mean +/- standard deviation [SD]: 3.7 +/- 2.4 vs. 0.8 +/- 1.3; p < 0.001) with significantly increased differences in levels II (1.4 +/- 0.8 vs. 0.3 +/- 0.5; p < 0.001), III (2 +/- 1.2 vs. 0.3 +/- 0.7; p < 0.001), and IV (0.7 +/- 0.7 vs. 0.07 +/- 0.2; p < 0.001). More nodes with a hilus were found in the CAT group than in the control group (mean number of nodes +/- SD: 2.8 +/- 1.9 vs. 0.7 +/- 1.1; p < 0.001). Short-axis diameter of level III (4.4 +/- 1 vs. 3.7 +/- 1.2 mm; p = 0.002) and level IV nodes (3.9 +/- 1 vs. 3.1 +/- 0.5mm p = 0.030) was increased in CAT patients when compared with healthy controls. Conclusions: The present study is the first one aiming at a systematic description of the sonographic pattern of cervical lymph nodes in CAT. An increased number of benign hyperplastic neck nodes, especially in levels II-IV, appears to be a characteristic sonographic finding associated with CAT.