Pathological findings of the retrospective diagnosis of NIFTP (non-invasive follicular thyroid neoplasm with papillary-like nuclear features) in 84 cases from Turkey and systematic review

• Published in: Annals of diagnostic pathology Vol. 53; p. 151764
• Main Authors: Turan, Gupse, Özkara, Sevgiye Kaçar
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.08.2021
• Subjects: Adenocarcinoma, Follicular - diagnosis; Adenocarcinoma, Follicular - radiotherapy; Adenocarcinoma, Follicular - surgery; Adenocarcinoma, Follicular - ultrastructure; Adult; Aged; Aged, 80 and over; Biopsy, Fine-Needle - methods; Cell Nucleus - pathology; Combined Modality Therapy; Female; Follicular variant of PTC; Follow-Up Studies; Humans; Incidence; Iodine Radioisotopes - therapeutic use; Male; Middle Aged; NIFTP; Non-invasive encapsulated FVPTC; Non-invasive follicular thyroid neoplasm with papillary-like nuclear features; Retrospective Studies; Thyroid; Thyroid Cancer, Papillary - diagnosis; Thyroid Cancer, Papillary - radiotherapy; Thyroid Cancer, Papillary - surgery; Thyroid Cancer, Papillary - ultrastructure; Thyroid Neoplasms - epidemiology; Thyroid Neoplasms - pathology; Thyroidectomy - methods; Turkey - epidemiology; Turkey; Non-invasive follicular thyroid neoplasm with papillary-like nuclear features; Non-invasive encapsulated FVPTC; NIFTP; Follicular variant of PTC; Thyroid
• ISSN: 1092-9134; 1532-8198
• DOI: 10.1016/j.anndiagpath.2021.151764

The terminology of “noninvasive follicular thyroid neoplasm with papillary-like nuclear features” (NIFTP) was introduced in 2016; and estimated to cause significant effects in the clinical management of thyroid nodules. The aim of our study is to review our cases that were previously diagnosed as non-invasive encapsulated follicular variant PTC (NI/E-FVPTC) which are compatible with NIFTP and to correlate their follow-up. All thyroidectomy cases evaluated in the last 15 years were screened, and possible NIFTP cases were determined among patients with NI/E-FVPTC and they were re-examined microscopically. Revised histopathological criteria were used for the retrospective diagnosis of NIFTP. Histopathological findings were correlated to follow up information. Totally 2138 cases had been previously diagnosed with PTC; 481 (22.5%) of them were FVPTC. After microscopic reevaluation of potential NIFTP cases, 84 cases (3.9%) received final diagnosis of NIFTP. 78.6% of NIFTP patients were female (F/M: 66/18); mean age was 49.0, tumor diameter was 22.7 mm and follow-up time was 66.4 months. 17.9% of NIFTP cases were multifocal and 13.1% were bilateral. No recurrence, lymph node involvement or distant metastasis was detected in any of the patients who were followed up. The mean age of the patients who had total thyroidectomy and received RAI was significantly higher than those who did not. Although conservative treatment of NIFTP with lobectomy is recommended, age of the patients has been continuing to be the most important determinant for the clinicians to decide on total thyroidectomy and RAI ablation therapy at our institution. •Terminology of "noninvasive follicular thyroid neoplasm with papillary-like nuclear features" (NIFTP) was introduced in 2016; and estimated to cause significant effects in the clinical management of thyroid nodules.•Totally 2138 cases had been previously diagnosed with PTC; 481 (22.5%) of them being FVPTC and 84 cases (3.9%) received final diagnosis of NIFTP.•17.9% of NIFTP cases were multifocal, 13.1% were bilateral and 11.9 % of patients had an associated micro-PTC.•Although no recurrence, lymph node involvement or distant metastasis was detected in any of the patients who were followed up; thyroid lobectomy was the index surgical procedure for only 10.7% and adjuvant treatment with RAI therapy was performed in 39.2% of patients.•Although conservative treatment of NIFTP with lobectomy is recommended, age of the patients has been continuing to be the most important determinant for the clinicians to decide on total thyroidectomy and RAI ablation therapy at our institution.