ABSTRACT
In 2015, the United States and Canadian Academy of Pathology re-evaluated noninvasive encapsulated follicular variant of papillary thyroid carcinomas (NI-EFVPC), and then the new terminology of "noninvasive follicular thyroid neoplasm with papillary-like nuclear features" (NIFTP) was initially introduced to replace NI-EFVPTC. In 2017, the World Health Organization also used NIFTP in the endocrine tumor classification. NIFTP is an encapsulated or clearly delimited noninvasive neoplasm with a follicular growth pattern and nuclear features of papillary thyroid carcinoma. Ultrasonography, cytology examination and genetic test are helpful to identify NIFTP, but the results overlap with invasive encapsulated follicular variant of papillary thyroid carcinoma. This paper mainly reviews the latest research in the clinical features, diagnosis and treatment features and prognosis of NIFTP.
ABSTRACT
Es bien conocido que ha existido en las últimas décadas un incremento en los casos de cáncer diferenciado de tiroides, especialmente los microcarcinomas. Diversos factores han contribuido a pesquisar pequeños cánceres como el aumento de la disponibilidad de exámenes imagenológicos. Estos pequeños cánceres tiroideos pueden tener un comportamiento no agresivo y no producir letalidad; esto es lo que se conoce como sobrediagnóstico. Esto último tiene implicancias tanto médicas como económicas por terapias agresivas. Así, desde el año 2015, un grupo de expertos cambia la nomenclatura en anatomía patológica del carcinoma papilar tiroideo variante folicular encapsulado (NIEFVPTC de sus siglas en inglés) por Neoplasia folicular tiroidea no invasiva con características nucleares de tipo papilar (NIFTP de sus siglas en inglés). Este cambio se basó en un estudio de Nikiforov donde los NIEFVPTC no tenían efectos adversos ni mortalidad en su seguimiento. Así, la intención inicial del cambio de nomenclatura es eliminar la palabra cáncer y evitar los sobretratamientos innecesarios. Presentamos un caso clínico de una paciente que se sometió a cirugía por un nódulo tiroideo clasificado Bethesda III donde la biopsia definitiva posterior a cirugía evidenció que se trataba de un NIFTP. A raíz de este caso analizamos la literatura hasta la fecha de esta nueva entidad y hacemos un repaso histórico de los carcinomas papilares tiroideos variante folicular. Además, desarrollamos nuevas interrogantes que se plantean desde este nuevo diagnóstico anatomopatológico, de cómo sospecharlo previo a una cirugía, cuál es la cirugía de elección, y cómo debiera ser el seguimiento una vez diagnosticado.
It is well known that there has been an increase in cases of differentiated thyroid cancer in recent decades, especially microcarcinomas. Several factors have contributed to diagnose small cancers such as the increased availability of imaging tests. These small thyroid cancers can have a non-aggressive behavior and not cause lethality, this is what is known as overdiagnosis. The latter has medical as well as economic implications for aggressive therapies. Thus, since 2015, a group of experts has changed the nomenclature in pathological anatomy of encapsulated variant papillary thyroid carcinoma (NIEFVPTC) for non-invasive thyroid follicular neoplasia with papillary nuclear characteristics (NIFTP). This change was based on a Nikiforov study where the NIEFVPTC had no adverse effects or mortality in their follow-up; thus, the initial intention of the nomenclature change is to eliminate the word cancer and avoid unnecessary over-treatments. We present a clinical case of a patient who underwent surgery for a thyroid nodule classified Bethesda III where the definitive biopsy after surgery showed that it was a NIFTP. Following this case, we analyze the literature to date of this new entity and make a historical review of the follicular variant papillary thyroid carcinomas. In addition, we develop new questions that arise from this new pathological diagnosis, how to suspect it prior to surgery, what is the surgery of choice, and what should the follow-up once diagnosed.
Subject(s)
Humans , Female , Adult , Thyroid Neoplasms/diagnosis , Thyroid Cancer, Papillary/diagnosis , Biopsy , Thyroid Neoplasms/surgery , Thyroid Neoplasms/pathology , Ultrasonography , Thyroid Cancer, Papillary/surgery , Thyroid Cancer, Papillary/pathologyABSTRACT
BACKGROUND: BRAF V600E mutation status and prevalence of non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) has not yet been reported in Korea. The aim of this study was to investigate the significance of the BRAF V600E mutation in the follicular variant of papillary thyroid carcinoma (FVPTC) and to determine the prevalence of NIFTP in BRAF V600E mutation-prevalent Korean patients. METHODS: This study retrospectively analyzed 1,417 consecutive patients who underwent total thyroidectomy with routine prophylactic central lymph node dissection for papillary thyroid carcinoma (PTC). BRAF V600E mutation analysis was performed routinely using multiplex polymerase chain reaction by applying dual priming oligonucleotide. Clinicopathological characteristics and ultrasonographic findings were compared between BRAF V600E mutation-positive and -negative groups for FVPTC. Pathologists reviewed the pathology slides according to consensus diagnostic criteria for the encapsulated FVPTC and NIFTP. RESULTS: The prevalence of the BRAF V600E mutation in all subtypes of PTC was 61.0% (861/1,411). FVPTC presented a BRAF V600E mutation rate of 27.3%. The FVPTC patients with BRAF V600E mutation were older than those with no BRAF V600E mutation (P = 0.021). The prevalence of NIFTP was 0.18% among all PTC patients (2/1,411) and the proportion of NIFTP among FVPTC was 9.1% (2/22). CONCLUSION: The BRAF V600E mutation is prevalent in Korean patients with FVPTC in a region with high frequency of the BRAF V600E mutation and very low prevalence of NIFTP compared with that reported in western studies.