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

Abstract

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.

Keywords: Borderline thyroid malignancy; Carcinoma papilar; Follicular variant; Neoplasia folicular de tiroides no invasiva con características de tipo papilar; Non-invasive follicular thyroid neoplasm with papillary-like features; Papillary carcinoma; Tumores tiroideos de malignidad intermedia; Variante folicular.