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Ancillary techniques play an essential role in pulmonary cytopathology. Immunoperoxidase and special stains are by far the most common ancillary techniques used in cytopathology; however, the role of molecular diagnosis is growing, especially in the fields of pulmonary oncology and infectious disease. In this article, we review the uses of ancillary techniques in lung tumor diagnosis, lung tumor classification, predictive marker determination, primary versus metastasis differential diagnosis, and infectious organism detection.

Objectives/UNASSIGNED:To evaluate whether non-small cell lung carcinoma (NSCLC) cytology specimens are reliable for programmed death-ligand 1 (PD-L1) immunohistochemical (IHC) testing. Methods/UNASSIGNED:Fifty-two cell blocks (CBs) with corresponding surgical pathology PD-L1 IHC testing were stained with a Dako PD-L1 pharmDX antibody (clone-22C3). Tumor cellularity was recorded as <100 or ≥100 cells. PD-L1 IHC was scored by percentage of tumor cells staining (<1%, ≥1%-49%, ≥50%) and compared between matched cases. Results/UNASSIGNED:Substantial agreement (κ = 0.63; 95% CI, 0.53-0.73) was reached between matched CB and surgical cases in CBs with ≥100 tumor cells compared to CBs with <100 tumor cells (slight agreement, κ = 0.19; 95% CI, 0.04-0.35). Overall, there was 67% agreement among paired cases (35/52 cases, κ = 0.51; 95% CI, 0.42-0.60). Conclusions/UNASSIGNED:CBs can be utilized for PD-L1 IHC testing, as illustrated by the 67% agreement between CB and surgical cases in our study. Disagreement is attributable to intratumoral heterogeneity and CB cellularity.

OBJECTIVE:Because of the indolent nature of Noninvasive Follicular Thyroid Neoplasm with Papillary-Like Nuclear Features (NIFTP) and potential requisite for conservative treatment, it is crucial to identify features of this entity pre-operatively. Our group recently published our findings that there are several cytomorphologic features that may be used as clues to distinguish NIFTP, PTC and follicular adenoma (FA) on fine-needle aspiration (FNA). Therefore, we aimed to determine the interobserver reproducibility of these findings. METHODS:Pre-surgical FNA slides from NIFTP (n=30), classic PTC (n=30) and FA (n=30) collected from 1/2013-8/2016 were reviewed by 7 cytopathologists blindly. Presence of selected cytomorphologic features was recorded and compared to determine percent agreement and inter-rater reliability among study cytopathologists using Gwet's AC1 statistics. RESULTS:For all the cytomorphologic features, the overall percent agreement amongst the pathologists ranged between 65.1% and 86.8% (Gwet's AC1 0.30 to 0.80). There was substantial or almost perfect agreement (Gwet's AC1 >0.60) in seven cytomorphologic features in the classic PTC group, in six features in the NIFTP group, and in five features in the FA group. There were no features with poor agreement (Gwet's AC1<0.0). CONCLUSIONS:The current study supports the reproducibility of our previous findings. The high level of agreement amongst pathologists for these groups, and particularly the NIFTP group, supports the notion that when viewed in combination as a cytologic profile, these cytomorphologic features may assist the cytopathologist in raising the possibility of NIFTP pre-operatively. This can potentially aid clinicians in deciding whether more conservative treatment may be appropriate.

Objectives/UNASSIGNED:Recognizing preoperative characteristics of noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) is important for clinical management. Therefore, we assessed presurgical NIFTP molecular profiles using fine-needle aspiration (FNA) material. Methods/UNASSIGNED:Presurgical FNA reports of 39 surgically confirmed NIFTP cases from January 2013 through May 2017 were assessed for Afirma and ThyroSeq results. Results/UNASSIGNED:Twenty-one of 39 NIFTP nodules were preoperatively tested with Afirma with two benign and 19 suspicious results. Twenty-seven of 39 nodules were tested with ThyroSeq (nine of 39 had both Afirma and Thyroseq): 18 (67%) had RAS mutations (13 NRAS, four HRAS, one KRAS), and three of 18 had multiple alterations (NRAS + TP53, n = 1; NRAS + PTEN, n = 2). BRAF T599_R603 + EIF1AX mutation (n = 1), PTEN mutation (n = 1), MET overexpression (n = 1), PAX8/PPARG fusion (n = 3), and THADA/IGF2BP3 fusion (n = 3) comprised the remainder. Conclusions/UNASSIGNED:NIFTP cases most commonly displayed suspicious Afirma results and RAS mutations on ThyroSeq, lacking aggressive/BRAF-V600E-like mutations. While NIFTP remains a surgical entity, the lack of aggressive/BRAF-V600E-like mutations can aid in determining the extent of surgery.

Background: Encapsulated follicular variant of papillary thyroid carcinoma (EFVPTC), formerly a malignant diagnosis and variant of PTC, has recently been reclassified to NIFTP on surgical pathology. Because of the indolent nature and potentially conservative treatment of NIFTP, it is crucial to identify features early on during patient evaluation which may suggest the possibility of this entity. One such feature is the molecular profile of thyroid nodules determined preoperatively utilizing fine-needle aspiration (FNA) cellular material. Design: Pre-surgical FNA Cytopathology reports of 41 confirmed cases of NIFTP from 1/2013-8/2016 were assessed for molecular testing (Afirma and/or ThyroSeq) results. Results: Bethesda System cytology diagnoses were: Benign (n=1), Atypia of Undetermined Significance (n=24), Follicular Neoplasm (n=14), and Suspicious for Malignancy (n=2). Of the 41 NIFTP cases, 22 nodules were pre-operatively tested with Afirma: 2 were benign; 20 were suspicious. 12 cases were Afirma MTC negative; 4 were BRAF negative. 27 nodules were pre-operatively tested with ThyroSeq: 2 had insufficient material; 15 cases (55.6%) had RAS mutations (11 NRAS, 4 HRAS); 3 of the 15 had two mutations [NRAS and TP53 (n=1); NRAS and PTEN (n=2)]. One additional case with 2 mutations showed BRAF T599-R603 and EIF1AX mutations (n=1). Other isolated molecular changes included PTEN mutation (n=1), MET overexpression (n=1), PAX8/PPARG fusion (n=4), and THADA/IGF2BP3 fusion (n=3). Conclusions: While NIFTP remains a surgical entity, the molecular profile of thyroid nodules can be analyzed pre-operatively in order to determine appropriate treatment. Our findings demonstrate that NIFTP cases most commonly displayed Suspicious Afirma results and RAS mutations on ThyroSeq, and several molecular alterations not characteristic of classical PTC or poorly differentiated/anaplastic thyroid carcinomas. The molecular profile of thyroid nodules must be considered together with the patients' clinical, sonographic and cytologic results in order to raise the possibility of NIFTP early on in determining proper management