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

Invited Review for the 100^th Anniversary of the TJEM

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

FRANCESCA MALETTA,¹ ENRICO COSTANTINO FALCO,² ALESSANDRO GAMBELLA,² JASNA METOVIC³ and MAURO PAPOTTI³

¹Pathology Unit, Department of Laboratory Medicine, AOU Città della Salute e della Scienza di Torino, Turin, Italy
²Pathology Unit, Department of Medical Sciences, University of Turin, Turin, Italy³Pathology Unit, Department of Oncology, University of Turin, Turin, Italy

In thyroid pathology, the great variety of types and the wide range of aggressiveness of thyroid cancers complicate both diagnosis and management. In 2016, a subset of noninvasive encapsulated follicular variant of papillary thyroid carcinoma was reclassified as noninvasive follicular thyroid tumor with papillary-like nuclear features (NIFTP) to reduce overtreatment of this low-risk tumor that follows a benign course after surgery. Starting from a paradigmatic clinical case, in this short review, we will summarize the ultrasonography, cytological, histological and molecular features of this new entity. In the preoperative settings, the recognition of some peculiar elements may only suggest the possibility of a NIFTP, thus favoring a less aggressive surgical approach. However, the diagnosis of NIFTP can only be made after complete resection of the lesion by detecting well-defined inclusion and exclusion histopathological criteria. Since NIFTP is not ‘malignant,' surgery may be considered curative with no further treatment or surveillance needed. NIFTP-related issues, including nodule size, multifocality, oncocytic changes, heterogeneous incidence across different geographical areas and its occurrence in the pediatric age, will be discussed.

Keywords —— borderline tumors; cytology; noninvasive follicular thyroid neoplasm with papillary-like nuclear features; thyroid; ultrasound

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Tohoku J. Exp. Med., 2020 252, 209-218.

Correspondence: Francesca Maletta, M.D., P Pathology Unit, Department of Laboratory Medicine, AOU Città della Salute e della Scienza di Torino, Via Santena 7, Turin 10127, Italy.

e-mail: francesca.maletta@libero.it