Atrophic changes identify a single DICER1-mutated nodule in sporadic adult thyroid follicular nodular disease...

The characterization of DICER1-associated thyroid disease has expanded in recent years, leading to growing interest in the morphological findings that may suggest an underlying DICER1 alteration. In this regard, atrophic changes (ACs) are nodular sclero-atrophic areas with flattened follicles that have emerged as a promising specific finding. However, their role is not yet universally recognized. Similarly, there is little experience with the use of an anti-DICER1 monoclonal antibody. This report describes a 56-year-old woman with sporadic thyroid follicular nodular disease (multinodular goiter), in whom only one of multiple nodules showed ACs, strong DICER1 immunoreactivity and a classic double somatic DICER1 hit. This observation further supports the potential value of ACs, complemented by DICER1 immunohistochemistry, in identifying the specific thyroid nodule most likely to harbor DICER1 alterations and therefore to be prioritized for molecular testing.