Comprehensive analysis for diagnosis of preoperative non-invasive follicular thyroid neoplasm with papillary-like nuclear features

Abstract

Objective The current paradigm in the treatment of patients with non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) is a diagnostic lobectomy rather than complete thyroidectomy and postoperative radioiodine treatment. Consequently, preoperative diagnosis of NIFTP is considered to be important. Methods We performed the comprehensive analysis for diagnosis of preoperative 20 NIFTPs in comparison with 41 invasive encapsulated follicular papillary thyroid carcinomas (I-EFVPTCs) using the Korean Thyroid Imaging Reporting and Data System (K-TIRADS), Bethesda System for Reporting Thyroid Cytopathology (TBSRTC), and molecular analysis for BRAF and RAS mutations. Results K-TIRADS 3 was identified as the most common sonographic diagnosis in both NIFTP and I-EFVPTC. Unlike I-EFVPTC, K-TIRADS 5 was not identified in NIFTP. AUS/FLUS was the most common cytopathological diagnosis and none of the cases were classified as malignant category in both groups, although the difference in distribution was not significant between the groups. BRAF mutation was not found in NIFTP but was present in 9.8% of cases in I-EFVPTC. The frequency of RAS mutation in I-EFVPTCs was twice as high as that of NIFTP. Wild-type BRAF and RAS in NIFTP was significantly higher than I-EFVPTC. Conclusion The existence of overlapping features between the groups was evident, hence conclusive distinction between radiology, cytology and molecular analysis could not be achieved. Apparently, the diagnosis of NIFTP based on comprehensive analysis was not confirmable but could perceive or at least favor the diagnosis of NIFTP.

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

“…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.…”

Noninvasive follicular thyroid neoplasm with papillary-like nuclear features: a problematic entity

“…Consequently, a high-suspicion pattern on US is significantly more frequent in IFVPTC than in NIFTP (51,82). However, studies suggest that ultrasonography is insufficient for differentiating NIFTP from invasive EFVPTC (80,81,83). Both tumours show a similar appearance in cytological examinations as well (58,76,80,83,84).…”

“…However, studies suggest that ultrasonography is insufficient for differentiating NIFTP from invasive EFVPTC (80,81,83). Both tumours show a similar appearance in cytological examinations as well (58,76,80,83,84). This is not surprising given that NIFTP can be differentiated from invasive EFVPTC by the exclusion of capsular and vascular invasion based on histological examination of the entire tumour along with the capsule (4,35).…”

“…The molecular profile of these tumours may prove helpful for the preoperative differentiation of NIFTP from invasive EFVPTC. Although RAS mutations occur in both tumour types with similar frequency (29, 30, 85), BRAF V600E and TERT promoter mutations are not found in NIFTP, whereas they may be present in a small percentage of invasive EFVPTC (29, 83,85,86,87).…”