incidence | Acta Medica Marisiensis

Objective: In 2016 a group of expert endocrine pathologists proposed a new terminology, NIFTP (Non-invasive follicular thyroid neoplasm with papillary-like nuclear features) for a histological subtype of thyroid carcinoma (encapsulated follicular variant of papillary thyroid carcinoma, non-invasive type). In this study, we aimed to assess on a retrospective basis the epidemiological trend and overall incidence of NIFTP in Mureș county, Romania, over a six-year period (2016-2021).
Methods: All NIFTPs registered between 2016-2021 in Târgu-Mureş Pathology Departments were reevaluated. NIFTP’s incidence was calculated by dividing the number of NIFTPs with the number of papillary thyroid carcinomas (PTCs). Further on, we compared NIFTP’s incidence between 2016-2018 with NIFTP’s incidence between 2019-2021, as the diagnostic criteria of NIFTP were revised in 2018.
Results: Forty-six cases of NIFTP were registered in our departments between 2016-2021, resulting in an overall NIFTP incidence of 17.9 % [CI (95%): 7.6-32.5] among the 257 PTCs. When we compared the NIFTP’ incidence between the two study periods (2016-2018 versus 2019-2021), our data revealed that the NIFTP’s overall incidence has dropped from 21.4 % [CI (95%): -14.5-60.1] to 15% [CI (95%): -8.2-43] in the second evaluated period (p=0.034).
Conclusion: The overall NIFTP incidence was low in our departments between 2016-2021. Moreover, NIFTP’s incidence decreased after 2018, following revision of the diagnostic criteria. Our results highlight that very stringent morphologic criteria need to be apply when making a diagnosis of NIFTP, in order to avoid a misdiagnosis and/or an overtreatment of a tumor with indolent behavior.

Papillary Thyroid Microcarcinomas: a 25 Years Retrospective, Institutional Study of 255 Cases

Zahan Ancuța Elena^1,2, Nechifor Boilă Adela^3*, Pașcanu Ionela^1,2, Voidăzan Septimiu⁴, Cătană Ramona¹, Fișus Andreea³, Borda Angela^3,5

1 Departament of Endocrinology, Emergency County Hospital, Tirgu Mures, Romania
2 Departament of Endocrinology, University of Medicine and Pharmacy of Tirgu Mures, Romania
3 Departament of Histology, University of Medicine and Pharmacy of Tirgu Mures, Romania
4 Departament of Epidemiology, University of Medicine and Pharmacy of Tirgu Mures, Romania
5 Departament of Pathology, Emergency County Hospital, Tirgu Mures, Romania

DOI: 10.1515/amma-2015-0108

Background: Papillary thyroid microcarcinoma (PTMC) defines a group of papillary thyroid carcinomas, incidentally discovered, measuring 1 cm or less. The aim of our study was to evaluate the incidence and the pathological characteristics of PTMCs in our institution in the last 25 years, with special emphasis on the prognostic factors related to PTMCs.
Material and methods: We performed a retrospective, cohort study on 255 PTMCs, registered in the Department of Pathology, Tîrgu-Mureş Emergency County Hospital between 1990 and 2014.
Results: A significant increase in the incidence of PTMCs was observed in the 2004-2014 period, compared to 1990-2003 (7.6%, 229 PTMCs/3005 thyroid specimens vs. 1.2%, 23 PTMCs/1885 thyroid specimens). Conventional PTMCs accounted for most of PTMC cases (n=123 cases, 48.2%), followed by the follicular variant of PTC (n=117 cases, 45.9%). The increasing incidence of PTMCs was associated with a significant increase in the routine number of blocks sampled per case over the study period (R2 =0.72, p < 0.001). By means of the univariate and multivariate analysis, three risk factors were predictive for extrathyroidal extension in PTMCs: multifocality (Odds ratio [OR] 4.97, p-0.002), tumor size ≥ 5mm (OR 8.97, p-0.008) and lymph node involvement (OR 17.66 p<0.005).
Conclusion: The incidence of PTMCs has revealed a significant increasing trend in our institution over the last 25 years. Multifocality, lymph node involvement and tumor size ≥ 5mm were found to be risk factors for extrathyroidal extension. These prognostic factors must be evaluated and clearly mentioned in the pathological report, to help a correct estimation of biological potential of the lesion and an appropriate postoperative management.