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Cytological Features of Noninvasive Follicular Thyroid Neoplasm with Papillary-like Nuclear Features (NIFTP)
Abstracts
Table 2
PST167 NIFTP - A Challenging Cytologic Diagnosis Lorene Yoxtheimer, MD, Neha Varshney, MD, Stacy Molnar, BS, SCT(ASCP), CT(IAC), Richard Cantley, MD. University of Toledo Medical Center, Toledo, OH Introduction: The encapsulated follicular variant of papillary thyroid carcinoma (PTC) has a better prognosis than conventional PTC and was, thereby, renamed noninvasive follicular thyroid neoplasm with papillarylike nuclear features (NIFTP) in 2015. A histologic diagnosis of NIFTP requires complete encapsulation without invasion of the tumor and a follicular growth pattern with less than 1% papillae. The nuclear features are almost identical to those found in PTC. Recent studies have shown that fine needle aspirations (FNAs) on NIFTP nodules typically yield diagnoses in the indeterminate category. Although NIFTP and PTC have overlapping nuclear features, they differ on a molecular basis. NIFTP lesions typically have RAS mutations, whereas PTCs have BRAF mutations. Materials and Methods: All thyroid lesions diagnosed as the follicular variant of papillary thyroid carcinoma between 2012 and 2016 were reviewed. The criteria of NIFTP were applied to these cases in order to determine how many would be diagnosed as NIFTP today. The FNAs of these NIFTP nodules prior to resection were evaluated. Results: Nine cases identified as the follicular variant of PTC had corresponding prior FNAs. Four of these cases were found to have extracapsular extension of the tumor and were, therefore, excluded from a diagnosis of NIFTP. Two of the cases with invasion had been diagnosed as the encapsulated follicular variant of PTC. Cytologic findings of the five remaining cases were reviewed. Three were diagnosed as papillary thyroid carcinoma, one was suspicious for malignancy, and one was diagnosed as a benign thyroid nodule. Conclusions: The cytologic diagnosis of NIFTP poses a diagnostic challenge because the nuclear features are similar to PTC. Molecular studies utilizing FNA material would aid in distinguishing NIFTP from PTC, saving patients with NIFTP from the complications associated with a total thyroidectomy and radioactive iodine.
S71 FNA is still a challenge because of lack of clear cytologic criteria. The objective is to correlate histologic proven NIFTP with prior cytologic interpretation based on the Bethesda system (TBS) and to evaluate various cytologic parameters in an attempt to identify any salient diagnostic features of NIFTP. Materials and Methods: A computerized search was preformed to identify all histologic cases which met the diagnostic criteria of NIFTP between 1999 and 2016. Corresponding FNA including both Diff-Quik and/or Papanicolaou stained slides were then retrieved and reviewed. For cases evaluated before the implementation of TBS in 2010, the interpretations were reviewed and placed into the best corresponding TBS diagnostic category. Results: A total of 55 cases of NIFTP with cyto-histologic correlation were retrieved. Forty-four patients (80%) were female. The mean patient age was 46 (range: 19-78). The mean nodule size was 2 cm (range: 0.6-4.5). About one-third of the nodules were solitary,, whereas the remaining two-thirds presented as a dominant nodule in a multinodular goiter setting. The preoperative cytology diagnoses were: 0(0%) non-diagnostic, 3(5%) benign, 5 (9%) atypia of undetermined significance, 34 (62%) suspicious for follicular neoplasm, 10 (18%) suspicious for malignancy, 3 (5%) positive for malignancy. Table 1 and 2 summarizes the cytologic and nuclear features of these 55 cases. Conclusion: According to TBS, most NIFTP were preceded by an AUS or suspicious for follicular neoplasm cytologic diagnoses. The typical cytologic features were a cellular aspirate with abundant small clusters and microfollicles of follicular with slightly enlarged, over crowded nuclei with frequent nuclear grooves, slightly clear chromatin, and mild irregular contours. Colloid was often scant and dense. Ill-defined nuclear inclusions were noted in w40% of cases but well-defined nuclear inclusions were infrequent.
Nuclear features of NIFTP
PST168 Cytological Features of Noninvasive Follicular Thyroid Neoplasm with Papillary-like Nuclear Features (NIFTP) Zesong Zhang, MD1, Manju Harshan, MD1, Xiaoyang Zheng, MD, PhD1, David Chhieng, MD, MBA2. 1Mount Sinai Health System, New York, NY; 2 University of Washington Medical Center, Seattle, WA Introduction: How to correctly diagnose recently designated noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) by
Cytological features of NIFTP
Table 2
PST167 NIFTP - A Challenging Cytologic Diagnosis Lorene Yoxtheimer, MD, Neha Varshney, MD, Stacy Molnar, BS, SCT(ASCP), CT(IAC), Richard Cantley, MD. University of Toledo Medical Center, Toledo, OH Introduction: The encapsulated follicular variant of papillary thyroid carcinoma (PTC) has a better prognosis than conventional PTC and was, thereby, renamed noninvasive follicular thyroid neoplasm with papillarylike nuclear features (NIFTP) in 2015. A histologic diagnosis of NIFTP requires complete encapsulation without invasion of the tumor and a follicular growth pattern with less than 1% papillae. The nuclear features are almost identical to those found in PTC. Recent studies have shown that fine needle aspirations (FNAs) on NIFTP nodules typically yield diagnoses in the indeterminate category. Although NIFTP and PTC have overlapping nuclear features, they differ on a molecular basis. NIFTP lesions typically have RAS mutations, whereas PTCs have BRAF mutations. Materials and Methods: All thyroid lesions diagnosed as the follicular variant of papillary thyroid carcinoma between 2012 and 2016 were reviewed. The criteria of NIFTP were applied to these cases in order to determine how many would be diagnosed as NIFTP today. The FNAs of these NIFTP nodules prior to resection were evaluated. Results: Nine cases identified as the follicular variant of PTC had corresponding prior FNAs. Four of these cases were found to have extracapsular extension of the tumor and were, therefore, excluded from a diagnosis of NIFTP. Two of the cases with invasion had been diagnosed as the encapsulated follicular variant of PTC. Cytologic findings of the five remaining cases were reviewed. Three were diagnosed as papillary thyroid carcinoma, one was suspicious for malignancy, and one was diagnosed as a benign thyroid nodule. Conclusions: The cytologic diagnosis of NIFTP poses a diagnostic challenge because the nuclear features are similar to PTC. Molecular studies utilizing FNA material would aid in distinguishing NIFTP from PTC, saving patients with NIFTP from the complications associated with a total thyroidectomy and radioactive iodine.
S71 FNA is still a challenge because of lack of clear cytologic criteria. The objective is to correlate histologic proven NIFTP with prior cytologic interpretation based on the Bethesda system (TBS) and to evaluate various cytologic parameters in an attempt to identify any salient diagnostic features of NIFTP. Materials and Methods: A computerized search was preformed to identify all histologic cases which met the diagnostic criteria of NIFTP between 1999 and 2016. Corresponding FNA including both Diff-Quik and/or Papanicolaou stained slides were then retrieved and reviewed. For cases evaluated before the implementation of TBS in 2010, the interpretations were reviewed and placed into the best corresponding TBS diagnostic category. Results: A total of 55 cases of NIFTP with cyto-histologic correlation were retrieved. Forty-four patients (80%) were female. The mean patient age was 46 (range: 19-78). The mean nodule size was 2 cm (range: 0.6-4.5). About one-third of the nodules were solitary,, whereas the remaining two-thirds presented as a dominant nodule in a multinodular goiter setting. The preoperative cytology diagnoses were: 0(0%) non-diagnostic, 3(5%) benign, 5 (9%) atypia of undetermined significance, 34 (62%) suspicious for follicular neoplasm, 10 (18%) suspicious for malignancy, 3 (5%) positive for malignancy. Table 1 and 2 summarizes the cytologic and nuclear features of these 55 cases. Conclusion: According to TBS, most NIFTP were preceded by an AUS or suspicious for follicular neoplasm cytologic diagnoses. The typical cytologic features were a cellular aspirate with abundant small clusters and microfollicles of follicular with slightly enlarged, over crowded nuclei with frequent nuclear grooves, slightly clear chromatin, and mild irregular contours. Colloid was often scant and dense. Ill-defined nuclear inclusions were noted in w40% of cases but well-defined nuclear inclusions were infrequent.
Nuclear features of NIFTP
PST168 Cytological Features of Noninvasive Follicular Thyroid Neoplasm with Papillary-like Nuclear Features (NIFTP) Zesong Zhang, MD1, Manju Harshan, MD1, Xiaoyang Zheng, MD, PhD1, David Chhieng, MD, MBA2. 1Mount Sinai Health System, New York, NY; 2 University of Washington Medical Center, Seattle, WA Introduction: How to correctly diagnose recently designated noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) by
Cytological features of NIFTP