CONTEXT: Noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) was introduced as a new entity replacing the diagnosis of noninvasive encapsulated follicular variant of papillary thyroid carcinoma (PTC). Significant variability in the incidence of NIFTP diagnosed in different world regions has been reported. OBJECTIVE: To investigate the rate of adoption of NIFTP, change in practice patterns, and uniformity in applying diagnostic criteria among pathologists practicing in different regions. METHODS: Two surveys distributed to pathologists of the International Endocrine Pathology Discussion Group with multiple-choice questions on NIFTP adoption into pathology practice and whole slide images of 5 tumors to collect information on nuclear score and diagnosis. Forty-eight endocrine pathologists, including 24 from North America, 8 from Europe, and 16 from Asia/Oceania completed the first survey and 38 the second survey. RESULTS: A 94% adoption rate of NIFTP by the pathologists was found. Yet, the frequency of rendering NIFTP diagnosis was significantly higher in North America than in other regions (P = .009). While the highest concordance was found in diagnosing lesions with mildly or well-developed PTC-like nuclei, there was significant variability in nuclear scoring and diagnosing NIFTP for tumors with moderate nuclear changes (nuclear score 2) (case 2, P < .05). Pathologists practicing in North America and Europe showed a tendency for lower thresholds for PTC-like nuclei and NIFTP than those practicing in Asia/Oceania. CONCLUSION: Despite a high adoption rate of NIFTP across geographic regions, NIFTP is diagnosed more often by pathologists in North America. Significant differences remain in diagnosing intermediate PTC-like nuclei and respectively NIFTP, with more conservative nuclear scoring in Asia/Oceania, which may explain the geographic differences in NIFTP incidence.

Anatomic Pathology Department of Medical and Surgical Sciences University of Bologna; Solid Tumor Molecular Pathology Laboratory IRCCS Azienda Ospedaliero University of Bologna Bologna 40138 Italy

Department of Anatomical Pathology Universitas Indonesia Dr Cipto Mangunkusumo Hospital Jakarta 10430 Indonesia

Department of Anatomical Pathology University of Texas MD Anderson Cancer Center Houston TX 77030 USA

Department of Hospital Pathology College of Medicine The Catholic University of Korea Seoul 06591 Republic of Korea

Department of Medical Biology and Pathology Institute Gustave Roussy Villejuif 94800 France

Department of Oncology Belarus Medical State University Minsk 220116 Belarus

Department of Pathology All India Institute of Medical Sciences New Delhi 110029 India

Department of Pathology and Immunology Washington University School of Medicine St Louis MO 63110 USA

Department of Pathology and Laboratory Medicine Mayo Clinic Arizona Scottsdale AZ 85259 USA

Department of Pathology and Laboratory Medicine Taipei Veterans General Hospital Taipei 11217 Taiwan

Department of Pathology and Laboratory Medicine University of California Los Angeles Los Angeles CA 90095 USA

Department of Pathology and Laboratory Medicine University of Pennsylvania Medical Center Perelman School of Medicine Philadelphia PA 19104 USA

Department of Pathology and Laboratory Medicine University of Wisconsin School of Medicine and Public Health Madison WI 53705 USA

Department of Pathology Cancer Genome Center and Thyroid Disease Center Izumi City General Hospital Izumi Osaka 594 0073 Japan

Department of Pathology Chulalongkorn University Bangkok 10330 Thailand

Department of Pathology Faculty of Medicine Gaziantep University Gaziantep 27310 Turkey

Department of Pathology Kameda Medical Center Kamogawa Chiba 296 8602 Japan

Department of Pathology King George's Medical University Lucknow 226003 India

Department of Pathology Massachusetts General Hospital Boston MA 02114 USA

Department of Pathology McGill University Montreal Quebec H3T 1E2 Canada

Department of Pathology Medical Faculty of Istanbul Istanbul University 34093 Istanbul Turkey

Department of Pathology Shanghai Sixth People's Hospital Shanghai 201306 China

Department of Pathology The University of Chicago Chicago IL 60637 USA

Department of Pathology University of Calgary Calgary Alberta T2N 2T9 Canada

Department of Pathology University of California San Francisco San Francisco CA 94143 USA

Department of Pathology University of Iowa Hospitals and Clinics Iowa City IA 52242 USA

Department of Pathology University of Pittsburgh Medical Center Pittsburgh PA 15213 USA

Department of Pathology University of Western Australia and Curtain Medical School Perth Western Australia 6102 Australia

Department of Pathology Yale School of Medicine New Haven CT 06510 USA

Division of Anatomic Pathology and Histology Fondazione Policlinico Agostino Gemelli IRCCS Università Cattolica del Sacro Cuore Rome 00168 Italy

The Fingerland Department of Pathology Charles University Medical Faculty and University Hospital Hradec Kralove 50005 Czech Republic

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