Noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) is a borderline thyroid tumour formerly known as noninvasive encapsulated follicular variant of papillary thyroid carcinoma. The prevalence of NIFTP is estimated at 4.4–9.1% of all papillary thyroid carcinomas worldwide; however, the rate of occurrence of NIFTP is eight times lower in Asian countries than in Western Europe and America. At the molecular level, NIFTP is characterised by the lack of BRAF V600E and BRAF V600E-like mutations or other high-risk mutations (TERT, TP53) and a high rate of RAS mutations, which is similar to other follicular-pattern thyroid tumours. The diagnosis of NIFTP can only be made after histological examination of the entire tumour removed during surgery and is based on strictly defined inclusion and exclusion criteria. Although the diagnosis is postoperative, the combination of certain findings of preoperative tests including ultrasonography, cytology, and molecular testing may raise suspicion of NIFTP. These tumours can be effectively treated by lobectomy, although total thyroidectomy remains an option for some patients. Radioactive iodine and thyroid stimulating hormone suppression therapy are not required. NIFTP has an extremely good prognosis, even when treated conservatively with lobectomy alone. Nevertheless, it cannot be considered as a benign lesion. The risk of adverse outcomes, including lymph node and distant metastases, is low but not negligible.
Klaudia Zajkowska, Janusz Kopczyński, Stanisław Góźdź, and Aldona Kowalska
Danuta Gąsior-Perczak, Iwona Pałyga, Monika Szymonek, Artur Kowalik, Agnieszka Walczyk, Janusz Kopczyński, Katarzyna Lizis-Kolus, Anna Słuszniak, Janusz Słuszniak, Tomasz Łopatyński, Ryszard Mężyk, Stanisław Góźdź, and Aldona Kowalska
Delayed risk stratification (DRS) system by Momesso and coworkers was accepted by the American Thyroid Association as a diagnostic tool for the risk stratification of unfavorable clinical outcomes and to monitor the clinical outcomes of differentiated thyroid cancer (DTC) patients treated without radioactive iodine (RAI). The aim of this study was to evaluate the DRS system in patients with pT1aN0/Nx stage.
The study included 304 low-risk patients after thyroidectomy (n = 202) or lobectomy (n = 102) without RAI and were treated at a single center. The median age was 50.5 years, 91.1% were women and the median follow-up was 4 years. DRS of the treatment response was performed based on medical records and according to the criteria of Momesso and coworkers. Disease course (recurrence, death) and status (remission, persistent disease) on December 31, 2016 were evaluated. The relationship between unfavorable outcomes and the DRS system was evaluated.
Response to initial therapy was excellent in 272 patients (89.5%), indeterminate in 31 (10.2%) and biochemical incomplete (increased TgAb levels) in one (0.3%). Two patients in the excellent response group experienced recurrence at 6 and 7 years of follow-up (after lobectomy). None of the patients with indeterminate and biochemical incomplete response developed structural disease, and none of the patients died during the follow-up.
The DRS system was not useful for predicting the risk of unfavorable clinical outcomes and cannot be used to personalize the monitoring method of the disease in patients at pT1aN0/Nx stage who are not treated with RAI.