Noninvasive follicular neoplasm with papillary like nuclear features: A comprehensive analysis with a diagnostic algorithm

Abstract

Background Noninvasive follicular thyroid neoplasm with papillary‐like nuclear features (NIFTP) lacks the carcinoma label, avoiding aggressive therapy, physiological, social and financial impact of cancer diagnosis. Unfortunately, the preoperative diagnosis is still a challenge. Varied incidence of NIFTP has been document with limited data on preoperative cytological, radiological characteristics and the impact on risk of malignancy in each category of the Bethesda system of reporting thyroid cytopathology. Method Retrospective analysis of 20 NIFTPs with an attempt to provide a preoperative diagnostic algorithm based on the cytological and ultrasound features along with incidence and implication on risk of malignancy in various Bethesda categories with its impact on patient management. Result Incidence of NIFTP in our study was higher in comparison to that documented from other Asian countries. TIRADS 3 was the most common sonographic diagnosis. NIFTP was commonly preceded by indeterminate or benign Bethesda category. Major impact of excluding NIFTP form malignant category was seen on Bethesda categories II and IV with 20% and 27% reduction in risk of malignancy, respectively. Conclusion Retrospective analysis should not be confined only to follicular variant of papillary thyroid carcinoma but cases of follicular adenoma and adenomatous colloid nodule should always be included in review to ascertain the true incidence of NIFTP. NIFTPs are less likely to have malignant preoperative cytology. NIFTP shares major cytological and ultrasound features with follicular adenoma, adenomatous colloid nodule and minimally invasive follicular papillary carcinoma. When analyzed together, taking minor findings in consideration, can favor a diagnosis.

Three ultrasound phenotypes of non-invasive follicular thyroid neoplasm with papillary-like nuclear features proposed for imaging-pathology analysis: single center experience

“…Gland Surg 2021;10(1):307-318 | http://dx.doi.org/10.21037/gs-20-612 rare with percentage ranging from 2.5% to 7.5% according to our data aggregation (12,13,17,18,20,21). The aggregated data also showed the echogenicity of NIFTP was unspecific with similar distribution between hypoecho/marked hypoecho and isoechoic/hyperecho (105/241, 43.5% vs. 136/241, 56.4%).…”

“…Type-B was identified more frequently in macrogroup of our cases, which means that it may be associated with NIFTP in larger size. The pooling data showed that partially cystic change occupies 20% among all types of component, therefore, this US subset of NIFTP should not be ignored (12,13,17,18,20,21). As for type-C, it contains NIFTP showing other suspected features, including irregular margin, nonparallel shape, and calcifications.…”

“…Since the formally proposal of NIFTP in 2016, 12 publications on the ultrasonography of NIFTP were identified till June 2020 (11)(12)(13)(17)(18)(19)(20)(21)(22)(23)(24)(25), one of which merely described the vascularity of NIFTP (19), and three of which generally reported the US features of NIFTP without requested details (22,23,25). After evaluation, 6 studies consisted of required US features of NIFTP (12,13,17,18,20,21). The pooled data of our cases combined with previous works were demonstrated in Table 3 and Figure 7.…”

Precursor and borderline lesions of the thyroid (indolent lesions of epithelial origin): from theory to practice

“…As Seethala et al (50) noticed, evaluating nuclear features of PTC as a "core diagnostic feature" of NIFTP should compare with the adjacent healthy thyroid tissue, which is not possible for cytology samples. Thus, the creation of a diagnostic algorithm to predict NIFTP by fine-needle aspiration biopsy (FNAB) has been proposed by cytopathologists (51). However, most studies supporting this proposal suffered from insufficient reproducibility.…”

Ultrasound findings of noninvasive follicular thyroid neoplasm with papillary-like nuclear features compared with those of follicular variant of papillary carcinoma and encapsulated papillary carcinoma: a single-institution study in Japan

“…Several studies have compared NIFTP and FVPTC (non-NIFTP) from various aspects including ultrasonic and pathological findings [4][5][6][7][8][9][10][11][12][13][14][15][16]. On ultrasound, the rate of findings suspected of malignancy in NIFTP was reported to be lower than that in non-NIFTP [10,11,[13][14][15]. In contrast, Hirokawa et al showed that on cytology, 75.7% of NIFTP cases were reported as suspicious for malignancy or malignant [4].…”