Ricardo R Lastra1, George Birdsong2, David H Hwang3, Merce Jorda4, Darcy A Kerr4, Cindy McGrath5, Shelley Odronic6, Rema Rao7, Paul A VanderLaan8, Joe W Walker9, Tatjana Antic10. 1. Department of Pathology and Laboratory Medicine, University of Chicago Medical Center, Chicago, Illinois. Electronic address: ricardo.lastra@uchospitals.edu. 2. Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia. 3. Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts. 4. Department of Pathology, University of Miami Miller School of Medicine, Miami, Florida. 5. Department of Pathology and Laboratory Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania. 6. Lima Pathology Associates, St. Rita's Medical Center, Lima, Ohio. 7. Papanicolaou Cytopathology Laboratory, Weill Cornell Medicine/New York Presbyterian Hospital, New York, New York. 8. Department of Pathology, Beth Israel Deaconess Medical Center, Boston, Massachusetts. 9. Department of Pathology, Rutland Regional Medical Center, Rutland, Vermont. 10. Department of Pathology and Laboratory Medicine, University of Chicago Medical Center, Chicago, Illinois.
Abstract
INTRODUCTION: Encapsulated follicular variant of papillary thyroid carcinoma (PTC) has an indolent behavior; hence, a change in terminology to "noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP)" has been proposed. Data are scant on the fine-needle aspiration (FNA) diagnosis of nodules proven to be NIFTP upon resection. The aim was to evaluate the FNA diagnosis of nodules diagnosed as NIFTP upon resection. MATERIALS AND METHODS: The archives of 8 participating institutions were searched for thyroid resection specimens obtained in a 1-year period, and pertinent demographic and pathology data were recorded. RESULTS: 2226 thyroid surgeries were performed over the indicated time period. NIFTP was diagnosed in 6.3% of cases; 118 patients (119 nodules) with NIFTP and available preoperative thyroid FNA were included. Preoperative cytologic diagnosis were: non-diagnostic: 0.8%; benign: 5.9%; atypia of undetermined significance/follicular lesion of undetermined significance: 42.9%; follicular neoplasm/suspicious for a follicular neoplasm: 31.0%; suspicious for malignancy: 15.9%; malignant: 3.4%. Molecular data was available for 49 cases, either by Afirma or ThyGenX/ThyroSeq. Of the Afirma cases, 11% were classified as "benign", 2% as "indeterminate", and 87% as "suspicious"; of the ThyGenX/ThyroSeq cases, 50% had NRAS mutations, 20% demonstrated KRAS mutations, 20% showed HRAS mutations, and 10% showed a BRAF mutation (K601E). CONCLUSIONS: NIFTP are tumors demonstrating nuclear features similar to those seen in PTC. Our series shows that a preoperative diagnosis of "suspicious for malignancy" or "malignant" is uncommon in NIFTP, suggesting that there are sufficient cytomorphologic differences between PTC and NIFTP to allow for the suspicion of NIFTP on FNA specimens.
INTRODUCTION: Encapsulated follicular variant of papillary thyroid carcinoma (PTC) has an indolent behavior; hence, a change in terminology to "noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP)" has been proposed. Data are scant on the fine-needle aspiration (FNA) diagnosis of nodules proven to be NIFTP upon resection. The aim was to evaluate the FNA diagnosis of nodules diagnosed as NIFTP upon resection. MATERIALS AND METHODS: The archives of 8 participating institutions were searched for thyroid resection specimens obtained in a 1-year period, and pertinent demographic and pathology data were recorded. RESULTS: 2226 thyroid surgeries were performed over the indicated time period. NIFTP was diagnosed in 6.3% of cases; 118 patients (119 nodules) with NIFTP and available preoperative thyroid FNA were included. Preoperative cytologic diagnosis were: non-diagnostic: 0.8%; benign: 5.9%; atypia of undetermined significance/follicular lesion of undetermined significance: 42.9%; follicular neoplasm/suspicious for a follicular neoplasm: 31.0%; suspicious for malignancy: 15.9%; malignant: 3.4%. Molecular data was available for 49 cases, either by Afirma or ThyGenX/ThyroSeq. Of the Afirma cases, 11% were classified as "benign", 2% as "indeterminate", and 87% as "suspicious"; of the ThyGenX/ThyroSeq cases, 50% had NRAS mutations, 20% demonstrated KRAS mutations, 20% showed HRAS mutations, and 10% showed a BRAF mutation (K601E). CONCLUSIONS:NIFTP are tumors demonstrating nuclear features similar to those seen in PTC. Our series shows that a preoperative diagnosis of "suspicious for malignancy" or "malignant" is uncommon in NIFTP, suggesting that there are sufficient cytomorphologic differences between PTC and NIFTP to allow for the suspicion of NIFTP on FNA specimens.