Investigating the possible association between thyroid nodule location and the malignancy risk of the nodules in FNA...

In this study we aimed to investigate the association between thyroid nodule location and the malignancy risk of the nodules in FNA samples.

In this cross sectional study, 400 patients with thyroid nodule size >1.5 cm, thyroid nodule size >1 cm with micro-calcification, and thyroid nodule size <1 cm with sonographic or clinical signs of malignancy who referred to a training hospital, were involved. Morphologic characteristics of nodules, including nodule size, laterality and polarity were recorded. In patients with multinodular goiter, the anatomical location was recorded and analyzed.

In our study, 345 female patients (86.3 %) and 55 male patients (13.8 %) with thyroid nodule were involved. The majority of thyroid nodules were identified in the right lobe (n = 182, 45.5 %) and left lobe (n = 177, 44.3 %), respectively. A total of 323 nodules were benign and the remaining (n = 77) were malignant. The frequency of malignancy in the upper pole of the thyroid (31.6 %) was higher compared to that in the middle pole (10.7 %), lower pole (19.1 %), and isthmus region (26.8 %), leading to a significant difference (p.value = 0.001). The mean size of thyroid nodules was 15.68 mm in benign nodules and 20.08 mm in malignant nodules.

Our results showed that thyroid nodules found in the upper lobe carried the greatest risk for malignancy. Accordingly, it seems that the location of thyroid nodules can be an independent risk factor in determining the malignancy risk of thyroid nodules and can be used to enhance clinical decision making in thyroid FNA samples.