Effect of non-invasive follicular thyroid neoplasm with papillary-like features (NIFTP) terminology on surgical management concepts

Background

Despite the strict diagnostic criteria recently proposed for non-invasive follicular thyroid neoplasm with papillary-like features (NIFTP), its incidence is still unknown. Employing a retrospective analysis of the follicular variant of papillary thyroid carcinoma (FVPTC), we investigated the diagnosis, prevalence and postoperative course of NIFTP.

Methods

We examined retrospectively the records of 112 patients who had undergone thyroid surgery and had a postoperative diagnosis of FVPTC at our hospital from 2010 to 2021. All clinical, radiologic, and pathologic features were evaluated.

Results

Only 34 (27.9%) patients met the strict pathologic criteria for NIFTP; 11 cases having been diagnosed as NIFTP initially and 23 after re-evaluation of histopathologic slides. None of the 11 NIFTP patients underwent a 2-stage operation, in contrast to 10 (29.4%) patients initially diagnosed as FVPTC who had a completion thyroidectomy after the initial hemithyroidectomy. The median follow-up was 14.5 (ranging from 0 to 78) months. None of the cases developed a recurrence.

Conclusion

To avoid unnecessary treatment or the follow-up advised for papillary thyroid carcinoma, clinicians and pathologists should be familiar with the terminology and the corresponding diagnostic criteria for NIFTP and their impact on management.