Noninvasive Follicular Thyroid Neoplasm With Papillary-Like Nuclear Features in Children: An Institutional Experience and Literature Review

Abstract

Background Papillary thyroid carcinoma (PTC) in children has a distinctive set of clinicopathologic features and molecular signature compared to their adult counterparts. The recent recommendation to reclassify encapsulated follicular variant of papillary thyroid carcinoma (EFVPTC) without invasion as noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) is based on evidence derived almost exclusively from studies in adults. Clinicopathologic studies restricted to pediatric NIFTP are limited. Methods We retrospectively analyzed all pediatric PTC and NIFTP diagnosed and treated in our institution from 1999 to 2016 (n = 31). Results Using recently published consensus diagnostic criteria, we identified 3 NIFTP and 2 infiltrative follicular variants of papillary thyroid carcinoma (FVPTC) among 31 cases. Two of the NIFTP cases were initially diagnosed as EFVPTC. All 3 patients with NIFTP had unifocal tumors of lower American Joint Committee on Cancer (AJCC) classification (T2 or lower) and were free of lymph node or distant metastasis. Total (n = 1) or completion (n = 2) thyroidectomy was performed in all cases, and only 1 NIFTP patient received subsequent radioablative therapy. No residual or recurrent disease has been observed during follow-up (15–138 months) in patients with NIFTP. Conclusions Our experience with NIFTP in children is similar to outcomes reported in adult studies, suggesting that pediatric NIFTP behave indolently as evidenced by the absence of local recurrence in our cohort.

Case Report: Multifocal non-invasive follicular thyroid neoplasm with papillary-like nuclear features presenting in a female child

“…Therefore, completion lobectomy is not recommended for postoperative cases diagnosed as NIFTP 8 . NIFTP in children has a similar outcome as cases reported in adults, suggesting that paediatric NIFTP behaves indolently, as evidenced by the absence of local recurrence and nodal metastasis 6 .…”

“…NIFTP cytology was commonly interpreted as follicular lesion of undetermined significance in 30% (categories III and IV according to Bethesda system), follicular neoplasm in 21%, suspicious for malignancy in 24%, malignant in 8%, bnign in 10% and non-diagnostic in 3% 11 , 12 . Although the above findings would suggest lobectomy, our patient was submitted for total thyroidectomy and as has been done in previously reported cases 6 , 7 , 9 , 10 .…”

“…Most NIFTP cases have been previously reported in adults and data concerning this diagnosis in children is scarce; only 21 cases in children have been reported in the English literature within the last two years ( Table 1 ) 6 – 10 . Preoperative diagnosis of our case was based on ultrasound data and the cytology was not obviously malignant.…”

Malignancy Rates by Bethesda Subcategory in the Pediatric Population

“…This entity which would have likely been called encapsulated follicular variant PTC in the past is fairly well-reported in the adult literature and is increasingly being reported in children. 17 Our data did not recognize any cases with a diagnosis of NIFTP, which was first introduced and incorporated into our institution in 2017. It is possible that some of malignant diagnoses in our data prior to this were in fact NIFTP but they were not able to be re-reviewed.…”

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

“…Since pediatric PTCs usually have clinicopathological and molecular features that differ from those of adults and tend to be more aggressive (with higher recurrence rates), many authors raise doubts and concern as to whether NIFTP in children should be treated in the same way as adults. However, the few reported NIFTP cases in the pediatric population showed an indolent behavior, with no lymph node or distant metastases or local recurrences (Rossi et al 2018;Rosario and Mourão 2018;Wang et al 2020). The current data therefore suggest that even pediatric NIFTP can be managed in a more conservative way, with lobectomy and no lymph node dissection or subsequent radioablation therapy.…”