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

Abstract

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.

Telomere-related Genomic Instability in Papillary Thyroid Cancers: A Preliminary Study

“…Our data clearly demonstrate that NIFTP has telomere signatures similar to FTA that is distinct from classical and follicular variants PTC. Although, NIFTP cannot be considered a benign lesion but rather a low-risk thyroid nodule, our results suggest and reinforce the idea that NIFTP are lesions more closely related to benign thyroid neoplasms, rather than to malignant lesions [18,19].…”

First bilateral non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) co-occurring with bilateral papillary thyroid microcarcinoma. Case report and literature review

“…The published cases we reviewed exhibited variable echogenicity on US scan. Such hypoechoic, hyperechoic or isoechogenic US findings [ 11 , 14 , 16 ] are supported by others who described NIFTP lesions as well-circumscribed with widely variable echogenicity [ 14 ]. In addition, initial US only showed the left sided complex cystic nodule; only on US guided FNA was the second nodule on the right side identified and aspirated.…”

Noninvasive Follicular Thyroid Neoplasm with Papillary-Like Nuclear Features: From Echography to Genetic Profile

“…In other cases, NIFTP may coexist with a carcinoma. A recent study by Zajkowska et al (2020) revealed that a synchronous malignant lesion could be present in a not negligible percentage of patients with NIFTP (15-46%, mostly papillary thyroid microcarcinomas): if this happens, NIFTP should not be included in TNM staging, as in general, only malignant tumors should be incorporated into the staging systems (Seethala et al 2018).…”