Nodule size and fine-needle aspiration biopsy: diagnostic challenges for thyroid malignancy

To investigate the relationship between nodule size and malignancy and the correlation between the dimensional parameter and fine-needle aspiration biopsy (FNAB) in patients with a nodular goiter.

Histological data of 415 patients who underwent thyroidectomy were used to estimate the actual nodule size and the difference between the diameter of the nodular lesion and the included tumor (intranodular peritumoral tissue [IPT]). FNAB was performed in 338 patients, and its predictive role was evaluated in comparison with histology.

The histology revealed 207 cases of thyroid malignancy. The mean nodule size was significantly larger in benign disease compared with malignant. Only age and FNAB malignant category were independently associated with malignancy. The IPT showed a trend toward a statistically significant association with FNAB malignant category.

Nodule size does not appear to be a reliable parameter to improve the clinical management of a nodular goiter because of a high variability between size of nodular area and tumor diameter.