Faculty Bibliography

Objectives/UNASSIGNED:Noninvasive encapsulated follicular variant of papillary thyroid carcinoma (NEFVPTC) was recently reclassified as noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP). Excluding "carcinoma" from the new terminology shifted NIFTP out of the malignant category and altered Bethesda System for Reporting Thyroid Cytopathology (BSRTC) rates of malignancy (ROMs) on thyroid fine-needle aspiration (FNA). Because of potential effects on management guidelines, we examined our ROM data. Methods/UNASSIGNED:In total, 750 thyroid FNAs with surgical resections from January 2013 to June 2016 were reviewed (including 87 NIFTPs). ROM was recorded for each BSRTC category: classifying NEFVPTC/NIFTP as "malignant" and reclassifying NEFVPTC/NIFTP as "nonmalignant." Results/UNASSIGNED:ROM changes were as follows: nondiagnostic (ND), no change; benign, 5.5% to 2.5%; atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS), 42.3% to 22.3%; follicular neoplasm/suspicious for follicular neoplasm (FN/SFN), 48.7% to 17.9%; suspicious for malignancy (SFM), 93.6% to 61.7%; and positive for malignancy, 100% to 97%. Conclusions/UNASSIGNED:Decreased ROM was seen in most BSRTC categories, most significantly in AUS/FLUS, FN/SFN, and SFM categories.

BACKGROUND: Noninvasive encapsulated follicular variant of papillary thyroid carcinoma, a diagnosis implying malignancy as a variant of papillary thyroid carcinoma (PTC), has recently been reclassified to noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) on surgical pathology. Due to the effects of such a recategorization on rate of malignancy and clinical management algorithms, it is imperative that we explore whether presurgical fine-needle aspiration can differentiate NIFTP from PTC and follicular adenoma (FA). METHODS: Cytology slides from subjects with final surgical pathology resection diagnoses of NIFTP/encapsulated follicular variant of papillary thyroid carcinoma, classic PTC, and FA made between January 2013 and August 2016 were assessed. The Bethesda System diagnoses were tabulated and cytomorphologic features were analyzed for an association with surgical pathology diagnoses. RESULTS: A total of 56 NIFTP, 67 classic PTC, and 30 FA cases were included. The presurgical NIFTP diagnosis according to The Bethesda System was most often atypia of undetermined significance (37.5%) followed by suspicious for follicular neoplasm/follicular neoplasm (26.8%), suspicious for malignancy (17.9%), benign (10.7%), and positive for malignancy (7.1%). The most common NIFTP cytomorphologic features were nuclear enlargement (83.9%), nuclear crowding (82.1%), nuclear clearing (69.6%), and microfollicles (73.2%). All cytomorphologic features demonstrated statistically significant associations (P value range, <.001-.002) between NIFTP and PTC, whereas select cytomorphologic features demonstrated significant associations between NIFTP and FA. CONCLUSIONS: Several statistically significant associations appear to be present between cytomorphologic features and surgical diagnosis that may be used as clues to distinguish NIFTP, PTC, and FA on fine-needle aspiration. Although diagnostic confirmation of NIFTP must occur at the time of excision, similar to follicular neoplasms, the possibility of NIFTP may be raised preoperatively on cytology. Cancer Cytopathol 2017;125:378-88. (c) 2017 American Cancer Society.

BACKGROUND: Encapsulated non-invasive follicular variant papillary thyroid cancer (ENIFVPTC) has recently been re-termed noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP). This designation specifically omits the word "cancer" to encourage conservative management since patients with NIFTP tumors have been shown to derive no benefit from completion thyroidectomy or adjuvant radioactive iodine (RAI) therapy. METHODS: IRB approved retrospective study of consecutive cases of tumors from 2007 to 2015 that met pathologic criteria for NIFTP. The Conservative Management (CM) group included patients managed with lobectomy alone or appropriately indicated total thyroidectomy. Those included in the Aggressive Management (AM) group received either completion thyroidectomy or radioactive iodine or both. RESULTS: From 100 consecutive cases of ENIFVPTC reviewed, 40 NIFTP were included for the final analysis. Of these, 10 (27%) patients treated with initial lobectomy received completion thyroidectomy and 6 of 37 (16%) also received post-surgical adjuvant RAI. The mean per-patient cost of care in the AM group was $17629+/-2865 nearly twice the $8637+/- 309 costs in the CM group, and was largely driven by the cost of completion thyroidectomy and RAI. CONCLUSIONS: The term NIFTP has been recently promulgated to identify a type of thyroid neoplasm, formerly identified as a low-grade cancer, for which initial surgery represents adequate treatment. We believe that since the new NIFTP nomenclature intentionally omits the word "cancer" the clinical indolence of these tumors will be better appreciated, and cost savings will result from a more conservative and appropriate clinical management.

The ETV6-NTRK3 translocation characterizes a subset of radiation associated and pediatric papillary thyroid carcinomas (PTCs). We now describe the clinicopathologic features of ETV6-NTRK3 translocated PTC in an adult population without radiation exposure. Twelve cases were identified by next-generation sequencing (ThyroSeq version 2). The mean patient age was 37 years with a female predilection (10:2). Preoperative fine needle aspiration was performed on 6 patients of which 4 were classified as "malignant," whereas 2 were classified as "follicular lesion of undetermined significance." One third (4/12) of patients demonstrated extrathyroidal extension and one half of patients (5/10) demonstrated lymph node metastases. One patient presented with brain metastasis. Tumors typically (8/12) demonstrated an admixture of follicular and papillary patterns and were usually infiltrative and multinodular (6/12 cases). Tumors often showed clear cell or oncocytic foci and demonstrated overt nuclear features of PTC, though characteristically, interspersed bland areas were common, even in metastases. Cytoplasmic vacuolization resembling that of mammary analog secretory carcinoma was also common but focal. TTF-1 was positive and S100 was negative in all tested cases confirming a thyroid phenotype. Unique morphologies included glomeruloid follicles, reverse polarization of nuclei. Survey of the TCGA datasets revealed similar findings. Thus, ETV6-NTRK3 translocated PTC are locoregionally aggressive and can metastasize distantly. They are characterized by mixture of papillary and follicular architecture and may show cytoplasmic vacuolization akin to other ETV6 translocated carcinomas. Although nuclear features are typically overt, interspersed bland regions may cause diagnostic difficulty in metastatic sites, and may explain discordance on fine needle aspiration.

BACKGROUND:Patient derived xenografts (PDXs) represent an essential tool in oncologic research, and we sought to further expand our repertoire of head and neck squamous cell carcinoma (HNSCC) while determining potential boundaries for this system. METHODS:We consented new patients for PDX development and determined if a 24-h time delay from tumor excision to xenograft implantation affected PDX establishment. We developed a tissue microarray (TMA) from formalin fixed, paraffin embedded PDXs and their subsequent passages and carried out quantitative immunohistochemistry for EGFR, pEGFR, pAkt, pERK and ERCC1. First and last passaged PDXs were compared via a paired t-test to examine for the stability of protein expression across passages. We performed a similar comparison of the mutational profile of the patient tumor and resulting xenografts using a targeted sequencing approach. RESULTS:No patient/tumor characteristics influenced PDX take rate and the 24-h time delay from tumor excision to xenograft implantation did not affect PDX establishment, growth or histology. There was no significant difference in biomarker expression between the first and last passaged PDXs for EGFR, pEGFR, pAkt, and ERCC1. For pERK there was a significant difference (p=0.002), but further analysis demonstrated this only arose in three of 15 PDXs. Targeted sequencing revealed striking stability of passenger and likely driver mutations from patient to xenograft. CONCLUSIONS:The stability of protein expression across PDX passages will hopefully allow greater investigation of predictive biomarkers in order to identify ones for further pre-clinical and clinical investigation.