Whether molecular testing adds diagnostic value to the evaluation of thyroid nodules 4-cm or larger is unknown. The impact of molecular testing on cytopathologic-histopathologic diagnosis of neoplasm (adenoma or malignant), stratified by nodule size <or≥ 4-cm, was analyzed from a surgical series. Of 490 index nodules, molecular testing was performed on 18% of 353 nodules <4-cm and 8.8% of 137 nodules ≥4-cm (p = 0.0118). Adenoma was higher (30% vs 14%) and malignancy lower in nodules ≥4-cm vs <4-cm (p < 0.0001). Molecular testing impacted the finding of malignancy in the <4-cm group. Molecular testing of the ≥4-cm AUS and FN cytology subcategory impacted neoplasm discovery (combining adenoma and malignancy), with mutation positive 100% (3/3), mutation negative 38% (3/8), no mutation testing 88% (21/24), p = 0.0122. In conclusion, more adenoma was found in nodules ≥4-cm, including those with benign cytology, which was not explained by available molecular testing results. Molecular testing impacted the finding of malignancy in thyroid nodules <4-cm. The overall number of ≥4-cm nodules with molecular testing in this study was too low to exclude its diagnostic value in this setting. Further study is recommended to include molecular testing in nodules ≥4-cm, including those with benign cytology, to identify follicular adenoma.
Bibliographical noteFunding Information:
This study was funded by the National Institutes of Health’s National Center for Advancing Translational Sciences, grant UL1TR002494. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health’s National Center for Advancing Translational Sciences.
© 2019, The Author(s).