Noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP): a review for clinicians

Abstract

Noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) is an encapsulated or clearly delimited, noninvasive neoplasm with a follicular growth pattern and nuclear features of papillary thyroid carcinoma (PTC). It is considered a ‘pre-malignant’ lesion of the RAS-like group. Ultrasonography (US), cytology and molecular tests are useful to suspect thyroid nodules that correspond to NIFTP but there is wide overlap of the results with the encapsulated follicular variant of PTC (E-FVPTC). In these nodules that possibly or likely correspond to NIFTP, if surgery is indicated, lobectomy is favored over total thyroidectomy. The diagnosis of NIFTP is made after complete resection of the lesion by observing well-defined criteria. In the case of patients who received the diagnosis of FVPTC and whose pathology report does not show findings of malignancy (lymph node metastasis, extrathyroidal invasion, vascular/capsular invasion), if the tumor was encapsulated or well delimited, the slides can be revised by an experienced pathologist to determine whether the diagnostic criteria of NIFTP are met, but special attention must be paid to the adequate representativeness of the capsule and tumor. Since NIFTP is not ‘malignant’, tumor staging is not necessary and patients are not submitted to thyroid cancer protocols or guidelines. We believe that patients with NIFTP without associated malignancy and without nodules detected by US of the remnant lobe (if submitted to lobectomy) can be managed like those with follicular adenoma.

Does noninvasive follicular thyroid neoplasm with papillary‐like nuclear features have distinctive features on sonography?

“…The sonographic features of NIFTP that were more similar to FA than to PTC included predominantly smooth borders, a lack of There is only one other study that examined the sonographic features of NIFTP. 6 In this study, cases of NIFTP on ultrasound were found to be of "low suspicion for malignancy" according to Haugen et al's American Thyroid Association pattern classifications. 1,6 In their study NIFTP more commonly displayed wider-than-tall shape, smooth borders, solid type nodules and lack of calcifications, findings similar to our study.…”

“…6 In this study, cases of NIFTP on ultrasound were found to be of "low suspicion for malignancy" according to Haugen et al's American Thyroid Association pattern classifications. 1,6 In their study NIFTP more commonly displayed wider-than-tall shape, smooth borders, solid type nodules and lack of calcifications, findings similar to our study. This study did not compare NIFTP to other benign or malignant entities, nor examine Doppler flow pattern or grade, findings that add more information to the literature as reported in our study ( In conclusion, our study demonstrates that NIFTP as compared to PTC, and as compared to FA display several distinguishing and several overlapping sonographic and Doppler features.…”

“…There is only one prior study in the literature evaluating the ultrasound features of NIFTP. 6 To the best of our knowledge, this paper is the first study to evaluate sonographic features of NIFTP and contrast them with the sonographic features of PTC and FA.…”

Thyroid FNA cytology in Asian practice—Active surveillance for indeterminate thyroid nodules reduces overtreatment of thyroid carcinomas

“…[53][54][55][56][57] This hypothesis was further supported by recent NIFTP studies that report that in some geographic areas of the world 10%-30% of newly diagnosed thyroid carcinomas could be re-designated as NIFTP, and significant numbers of NIFTPs were classified in the indeterminate cytological categories. [58][59][60][61][62][63][64][65][66][67][68] However, the improved prognosis of thyroid carcinomas in inde- Kobe, Japan. 22 The cytological-histological correlation study, including biopsies for non-surgical cases, such as undifferentiated carcinomas and malignant lymphomas, is summarised in…”

Sonographic and cytologic differences of NIFTP from infiltrative or invasive encapsulated follicular variant of papillary thyroid carcinoma

“…Ultrasound [16][17][18] and cytologic studies [19][20][21][22][23][24] useful in the differentiation of NIFTP from PTC are summarized in Table I.…”