Genomic Staging of Multifocal Lung Squamous Cell Carcinomas Is Independent of the Comprehensive Morphologic Assessment.

INTRODUCTION: Morphologic and molecular data for staging of multifocal lung squamous cell carcinomas (LSCCs) are limited. In this study, whole exome sequencing (WES) was used as the gold standard to determine whether multifocal LSCC represented separate primary lung cancers (SPLCs) or intrapulmonary metastases (IPMs). Genomic profiles were compared with the comprehensive morphologic assessment. METHODS: WES was performed on 20 tumor pairs of multifocal LSCC and matched normal lymph nodes using the Illumina NovaSeq6000 S4-Xp (Illumina, San Diego, CA). WES clonal and subclonal analysis data were compared with histologic assessment by 16 thoracic pathologists. In addition, the immune gene profiling of the study cases was characterized by the HTG EdgeSeq Precision Immuno-Oncology Panel. RESULTS: By WES data, 11 cases were classified as SPLC and seven cases as IPM. Two cases were technically suboptimal. Analysis revealed marked genomic and immunogenic heterogeneity, but immune gene expression profiles highly correlated with mutation profiles. Tumors classified as IPM have a large number of shared mutations (ranging from 33.5% to 80.7%). The agreement between individual morphologic assessments for each case and WES was 58.3%. One case was unanimously interpreted morphologically as IPM and was in agreement with WES. In a further 17 cases, the number of pathologists whose morphologic interpretation was in agreement with WES ranged from two (one case) to 15 pathologists (one case) per case. Pathologists showed a fair interobserver agreement in the morphologic staging of multiple LSCCs, with an overall kappa of 0.232. CONCLUSIONS: Staging of multifocal LSCC based on morphologic assessment is unreliable. Comprehensive genomic analyses should be adopted for the staging of multifocal LSCC.

Assessment of the feasibility of frozen sections for the detection of spread through air spaces (STAS) in pulmonary adenocarcinoma.

Spread through air spaces (STAS) is reportedly associated with worse prognosis in sublobar resections of lung adenocarcinoma. Recently, it was proposed that STAS detected on frozen sections can be an indication for lobectomy instead of sublobar resection. We undertook this study to evaluate the reliability of STAS assessment on frozen sections compared to permanent sections, as well as the associations among STAS, tumor grade, and recurrence-free survival (RFS) after sublobar resection. A total of 163 stage I lung adenocarcinoma resections with frozen sections were identified retrospectively. For each case, and for frozen and permanent sections separately, the presence or absence of STAS, as well as the tumor grade, were recorded. Compared to permanent sections, STAS detection on frozen sections had low sensitivity (55%), low positive predictive value (48%), and fair agreement (K = 0.34), whereas there was higher specificity (80%) and negative predictive value (85%). Accuracy was 74%. Tumor grade assessment on frozen sections showed higher sensitivity (77%), positive predictive value (90%), agreement (K = 0.72), specificity (94%), and accuracy (87%), and the same negative predictive value (85%). High-grade histology on frozen sections was associated with shorter RFS (p = 0.02), whereas STAS on frozen sections was not (p = 0.47). Our results suggest that the intraoperative detection of STAS has low sensitivity and positive predictive value. False-positive results may lead to overtreatment of patients with lung cancer. The determination of tumor grade on frozen sections offers better sensitivity and specificity, plus it is associated with RFS, whereas STAS on frozen sections is not. Further study is needed to explore the utility of assessing tumor grade on frozen sections.

Accuracy and Reproducibility of Intraoperative Assessment on Tumor Spread Through Air Spaces in Stage 1 Lung Adenocarcinomas.

INTRODUCTION: Tumor spread through air spaces (STAS) is associated with worse prognosis in early-stage lung adenocarcinomas, particularly in sublobar resection. Intraoperative consultation for STAS has been advocated to guide surgical management. However, data on accuracy and reproducibility of intraoperative assessment of STAS remain limited. We evaluated diagnostic yield, interobserver agreement (IOA), and intraobserver agreement (ITA) for STAS detection on frozen section (FS). METHODS: A panel of three pathologists evaluated stage 1 lung adenocarcinomas (n = 100) for the presence or absence of STAS and artifacts as reference. Five pulmonary pathologists independently reviewed all cases in two rounds, detecting STAS and artifacts in FS and the corresponding FS permanent and non-FS permanent, with a consensus conference between rounds. RESULTS: The FS had low sensitivity (44%), high specificity (91%), relatively high accuracy (71%), and overall area under the receiver operating characteristic curve of 0.67 for detecting STAS. The average ITA was moderate for both STAS (κmean: 0.598) and artifact (κmean: 0.402) detection on FS. IOA was moderate for STAS (κround-1: 0.453; κround-2: 0.506) and fair for artifact (κround-1: 0.300; κround-2: 0.204) detection on FS. IOA for STAS improved in FS permanent and non-FS permanent, whereas ITA was similar across section types. On multivariable logistic regression, the only significant predictor of diagnostic discordance was the presence of artifacts. CONCLUSIONS: FS is highly specific but not sensitive for STAS detection in stage 1 lung adenocarcinomas. IOA on STAS is moderate in FS and improved only marginally after a consensus conference, raising concerns regarding global implementation of intraoperative assessment of STAS and warranting more precise criteria for STAS and artifacts.

Objective assessment of tumor regression in post-neoadjuvant therapy resections for pancreatic ductal adenocarcinoma: comparison of multiple tumor regression grading systems.

Neoadjuvant therapy is increasingly used to control local tumor spread and micrometastasis of pancreatic ductal adenocarcinoma (PDAC). Pathology assessments of treatment effects might predict patient outcomes after surgery. However, there are conflicting reports regarding the reproducibility and prognostic performance of commonly used tumor regression grading systems, namely College of American Pathologists (CAP) and Evans' grading system. Further, the M.D. Anderson Cancer Center group (MDA) and the Japan Pancreas Society (JPS) have introduced other grading systems, while we recently proposed a new, simple grading system based on the area of residual tumor (ART). Herein, we aimed to assess and compare the reproducibility and prognostic performance of the modified ART grading system with those of the four grading systems using a multicenter cohort. The study cohort consisted of 97 patients with PDAC who had undergone post-neoadjuvant pancreatectomy at four hospitals. All patients were treated with gemcitabine and S-1 (GS)-based chemotherapies with/without radiation. Two pathologists individually evaluated tumor regression in accordance with the CAP, Evans', JPS, MDA and ART grading systems, and interobserver concordance was compared between the five systems. The ART grading system was a 5-tiered system based on a number of 40× microscopic fields equivalent to the surface area of the largest ART. Furthermore, the final grades, which were either the concordant grades of the two observers or the majority grades, including those given by the third observer, were correlated with patient outcomes in each system. The interobserver concordance (kappa value) for Evans', CAP, MDA, JPS and ART grading systems were 0.34, 0.50, 0.65, 0.33, and 0.60, respectively. Univariate analysis showed that higher ART grades were significantly associated with shorter overall survival (p = 0.001) and recurrence-free survival (p = 0.005), while the other grading systems did not show significant association with patient outcomes. The present study revealed that the ART grading system that was designed to be simple and more objective has achieved high concordance and showed a prognostic value; thus it may be most practical for assessing tumor regression in post-neoadjuvant resections for PDAC.

Histopathologic Assessment of Suspected Idiopathic Pulmonary Fibrosis: Where We Are and Where We Need to Go.

CONTEXT.­: Accurate diagnosis of idiopathic pulmonary fibrosis (IPF) requires multidisciplinary diagnosis that includes clinical, radiologic, and often pathologic assessment. In 2018, the American Thoracic Society, European Respiratory Society, Japanese Respiratory Society, and the Latin American Thoracic Society (ATS/ERS/JRS/ALAT) and the Fleischner Society each published guidelines for the diagnosis of IPF, which include criteria for 4 categories of confidence of a histologic usual interstitial pneumonia (UIP) pattern. OBJECTIVE.­: To (1) identify the role of the guidelines in pathologic assessment of UIP; (2) analyze the 4 guideline categories, including potential areas of difficulty; and (3) determine steps the Pulmonary Pathology Society and the greater pulmonary pathology community can take to improve current guideline criteria and histopathologic diagnosis of interstitial lung disease. DATA SOURCES.­: Data were derived from the guidelines, published literature, and clinical experience. CONCLUSIONS.­: Both guidelines provide pathologists with a tool to relay to the clinician the likelihood that a biopsy represents UIP, and serve as an adjunct, not a replacement, for traditional histologic diagnosis. There are multiple challenges with implementing the guidelines, including (1) lack of clarity on the quantity and quality of histologic findings required, (2) lack of recognition that histologic features cannot be assessed independently, and (3) lack of guidance on how pathologists should incorporate clinical and radiographic information. Current criteria for "probable UIP" and "indeterminate for UIP" hinder accurate reflection of the likelihood of IPF. These challenges highlight the need for further morphologic-based investigations in the field of pulmonary pathology.

Quantitative assessment of PD-L1 as an analyte in immunohistochemistry diagnostic assays using a standardized cell line tissue microarray.

Programmed death 1 ligand 1 (PD-L1) Immunohistochemistry (IHC) is the key FDA-approved predictive marker to identify responders to anti-PD1 axis drugs. Multiple PD-L1 IHC assays with various antibodies and cut points have been used in clinical trials across tumor types. Comparative performance characteristics of these assays have been extensively studied qualitatively but not quantitatively. Here we evaluate the use of a standardized PD-L1 Index tissue microarray (TMA) to objectively determine agreement between antibody assays for PD-L1 applying quantitative digital image analysis. Using a specially constructed Index TMA containing a panel of ten isogenic cell lines in triplicate, we tested identical but independently grown batches of isogenic cells to prove Index TMAs can be produced in large quantities and hence serve as a standardization tool. Then the Index TMAs were evaluated using quantitative immunofluorescence (QIF) to validate the TMA itself and also to compare antibodies including E1L3N, SP142 and SP263. Next, an inter-laboratory and inter-assay comparison of 5 PD-L1 chromogenic IHC assays (US Food and Drug Administration (FDA) approved and lab developed test (LDT)) were performed at 12 sites around the USA. As previously reported, the SP142 FDA assay failed to detect low levels of PD-L1 in cell lines distinguished by the other four assays. The assays for 22C3 FDA, 28-8-FDA, SP263 FDA, and E1L3N LDT were highly similar across sites and all laboratories showed a high consistency over time for all assays using this Index TMA. In conclusion, we were able to objectively quantify PD-L1 expression on a standardized Index TMA using digital image analysis and we confirmed previous subjective assessments of these assays, but now in a multi-institutional setting. We envision commercial use of this Index TMA or similar smaller version as a useful standardization mechanism to compare results between institutions and to identify abnormalities while running routine clinical samples.

Number of Examined Lymph Nodes and Nodal Status Assessment in Distal Pancreatectomy for Body/Tail Ductal Adenocarcinoma.

OBJECTIVE: First, to assess the impact of the number of examined lymph nodes (ELNs) on staging and survival after distal pancreatectomy (DP) for pancreatic adenocarcinoma (PDAC). Second, to identify the minimum number of ELNs (MNELNs) ensuring an accurate detection of nodal involvement. Third, to reappraise the role of lymph node (LN) parameters, including N-status and lymph node ratio (LNR). BACKGROUND: In contrast with pancreatoduodenectomy, information on LN staging and the MNELN required in DP is lacking. METHODS: Patients undergoing DP for PDAC at 2 academic hospitals from 2000 through 2013 were retrospectively analyzed. The eighth edition of the American Joint Committee on Cancer staging system was used. The MNELN was estimated using the binomial probability law. Survival analyses were performed separately for node-negative and node-positive patients using univariable and multivariable models. RESULTS: The study population consisted of 240 patients. The median number of ELN was 21, significantly lower in node-negative patients as compared with node-positive patients (18.5 vs 24.0; P = 0.001). The proportion of node-positive patients increased with increasing numbers of ELNs, whereas LNR showed an inverse trend. The estimated MNELN was 20. The number of ELN (≥ or <20) was an independent prognostic factor only in node-negative patients [odds ratio (OR) 3.23 for ELN <20), suggesting a stage migration effect. In node-positive patients, N2-class, but not LNR, was a significant predictor of survival at multivariable analysis (OR 1.68). CONCLUSION: The number of ELN affects nodal staging in body/tail PDAC. At least 20 LNs are required for correct staging. N-status is superior to LNR in predicting survival of node-positive patients.

Neutrophilic infiltration in gluten-sensitive enteropathy is neither uncommon nor insignificant: assessment of duodenal biopsies from 267 pediatric and adult patients.

The histologic findings of celiac disease, that is, gluten-sensitive enteropathy (GSE), are dominated by increased intraepithelial lymphocytes, villous blunting, lymphoplasmacytic infiltration of lamina propria, and crypt hyperplasia. To date, neutrophils have not been thought to constitute a significant cell type in GSE, and their presence often invokes consideration of alternative diagnoses. Thus, we sought to determine the prevalence and severity of neutrophilic infiltration in duodenal biopsies from patients with GSE. The degree of neutrophilic infiltration and features characteristic of GSE were assessed in duodenal biopsies from 267 clinically confirmed GSE patients (116 adults and 151 children). These specimens were graded by the disease activity score (DAS) and the neutrophilic activity score (NAS). Gastric antral biopsies obtained from 195 patients were also evaluated for lymphocytic gastritis. NAS was correlated with DAS and other clinicopathologic features. We found that 56% of pediatric and 28% of adult GSE patients had significant duodenal neutrophilia. NAS was higher in children than in adults (2.3 vs. 1.2, P<0.001). Multivariate regression showed that DAS, eosinophilic infiltration, and foveolar metaplasia correlated positively, and age correlated negatively with NAS. Lymphocytic gastritis was seen in 21.5% of the gastric biopsies. The presence of lymphocytic gastritis correlated positively with NAS and DAS, and in the pediatric population it correlated negatively with age. Significant duodenal neutrophilia is often found in patients with celiac disease, especially in the pediatric population, and is associated with more active disease. Thus, the findings of duodenal neutrophilia in biopsies, otherwise consistent with GSE, should not preclude the diagnosis of GSE.

Cytological analysis of small branch-duct intraductal papillary mucinous neoplasms provides a more accurate risk assessment of malignancy than symptoms.

OBJECTIVES: The Sendai guidelines for management of patients with clinically suspected intraductal papillary mucinous neoplasms (IPMN) recommend resection of cysts > 30 mm, a dilated main pancreatic duct (MPD) > 6 mm, a mural nodule (MN), symptoms or positive cytology. Although sensitive, asymptomatic cysts, nonspecific symptoms, and a high threshold for positive cytology limit the specificity of the guidelines. We have assessed the value of cytology relative to symptom for predicting malignancy in IPMNs without high-risk imaging features. MATERIALS AND METHODS: We retrospectively reviewed the clinical, radiological, and cytological data of 31 small branch-duct IPMNs without a MN. The cytological presence of high-grade atypical epithelial cells (HGA) was considered true positive, with a corresponding histology of high-grade dysplasia or invasive carcinoma. The performance of cytology versus symptoms was evaluated by calculating the sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), and accuracy. RESULTS: The sensitivity (0.80), specificity (0.85), and accuracy (0.84) of HGA were higher than the corresponding performance characteristics of symptoms (0.60, 0.45, and 0.48, respectively). The NPV of no HGA on cytology was > 95%. CONCLUSIONS: Cytology is a better predictor of malignancy than symptoms, for the conservative management of small branch-duct IPMNs. Cytology contributes to a highly accurate triple negative test for malignancy in small IPMN: No dilated MPD, MN or HGA.

Cytology adds value to imaging studies for risk assessment of malignancy in pancreatic mucinous cysts.

OBJECTIVE: Evaluate the value of cytology relative to imaging features in risk assessment for malignancy as defined in the Sendai Guidelines. BACKGROUND: The Sendai Guidelines list symptoms, cyst size >30 mm, dilated main pancreatic duct (MPD) >6 mm, mural nodule (MN) and "positive" cytology as high risk stigmata for malignancy warranting surgical triage. METHODS: We reviewed clinical, radiological and cytological data of 112 patients with histologically confirmed mucinous cysts of the pancreas evaluated in a single tertiary medical center. Cytology slides were blindly re-reviewed and epithelial cells grouped as either benign or high-grade atypia (HGA) [≥high-grade dysplasia]. Histologically, neoplasms were grouped as benign (low-grade and moderate dysplasia) and malignant (in situ and invasive carcinoma). Performance characteristics of cytology relative to other risk factors were evaluated. RESULTS: Dilated MPD, MN, and HGA were independent predictors of malignancy (p < 0.0001), but not symptoms (p = 0.29) or cyst size >30 mm (p = 0.51). HGA was the most sensitive predictor of malignancy in all cysts (72%) and in small (≤30 mm) branch-duct intraductal papillary mucinous neoplasm (BD IPMN; 67%), whereas also being specific (85 and 88%, respectively). MN and dilated MPD were highly specific (>90%), but insensitive (39%-44%). Cytology detected 30% more cancers in small cysts than dilated MPD or MN and half of the cancers without either of these high-risk imaging features. CONCLUSIONS: Cytology adds value to the radiological assessment of predicting malignancy in mucinous cysts, particularly in small BD IPMN.

Prospective evaluation of MR enterography as the primary imaging modality for pediatric Crohn disease assessment.

OBJECTIVE: The objectives of this study were prospective evaluation of MR enterographic accuracy for detecting Crohn disease imaging features in pediatric patients, compared with a CT reference standard, as well as determination of MR enterographic accuracy for detecting active bowel inflammation and fibrosis using a histologic reference standard. SUBJECTS AND METHODS: The study group for this blinded prospective study included 21 pediatric subjects with known Crohn disease scheduled for clinical CT and histologic bowel sampling for symptomatic exacerbation. All subjects and their parents gave informed consent to also undergo MR enterography. CT and MR enterography examinations were independently reviewed by two radiologists and were scored for Crohn disease features. All bowel histology specimens were reviewed by a single pathologist for the presence of active mucosal inflammation and mural fibrosis, followed by correlation of imaging and histologic findings. RESULTS: All 21 subjects underwent MR enterography and histologic sampling, 18 of whom also underwent CT. MR enterography had high sensitivity for detecting Crohn disease imaging features (e.g., bowel wall thickening, mesenteric inflammation, lymphadenopathy, fistula, and abscess) compared with CT, with individual sensitivity values ranging from 85.1% to 100%. Of a total of 53 abnormal bowel segments with correlation of MRI and histologic findings, MR enterography showed 86.7% accuracy (90.0% sensitivity and 82.6% specificity) for detecting active inflammation (p < 0.001). The accuracy of MR enterography for detecting mural fibrosis overall was 64.9%, compared with histology, but increased to 83.3% (p < 0.05) for detecting fibrosis without superimposed active inflammation. CONCLUSION: MR enterography can substitute for CT as the first-line imaging modality in pediatric patients with Crohn disease, on the basis of its ability to detect intestinal pathologic abnormalities in both small and large bowel as well as extraintestinal disease manifestations. Additionally, MR enterography provides an accurate noninvasive assessment of Crohn disease activity and mural fibrosis and can aid in formulating treatment strategies for symptomatic patients and assessing therapy response.

Leaks and endoscopic assessment of break of integrity after NOTES gastrotomy: the LEAKING study, a prospective, randomized, controlled trial.

BACKGROUND: Gastric leak testing after natural orifice transluminal endoscopic surgery (NOTES) gastrotomy closure may help reduce the risk of leaks after transgastric procedures. OBJECTIVE: To develop a novel endoscopy-based system to determine the presence of a leak after NOTES gastrotomy and to compare this system prospectively with radiographic leak testing. DESIGN: Prospective, randomized, controlled trial. SETTING: Academic Medical Center laboratory. SUBJECTS: Fifty swine. INTERVENTION: During the pretrial phase, an endoscopic system for the measurement of intragastric pressure was developed. In the trial phase, swine with a NOTES gastrotomy were randomized to endoscopic versus radiographic leak testing. If a leak was demonstrated, the gastrotomy was reclosed by using a second-generation prototype T-anchor system. The primary outcome was leak detection after gastrotomy closure. The secondary outcome variables included necropsy findings, peritoneal fluid analysis, histologic examination, and clinical outcome. RESULTS: Fourteen swine were included in the pretrial phase and 36 in the randomized trial. Swine were survived for a mean of 9 days postoperatively. Endoscopic pressure monitoring demonstrated a reproducible change in intragastric pressure with insufflation; r = 0.735, P = .001 and r = 0.769, P < or = .000 for the total and maximum pressures, respectively. Post-peritoneoscopy, there was a detectable and significant decrease in the mean total and mean maximum pressures versus baseline (P = .006 and P = .009). There was no significant difference between the radiologic and endoscopic arms in leak detection rate (4/18 vs 3/18, respectively, P = .500). Clinical outcomes and mean weight gain were equivalent. There was 1 operative abdominal wall injury and no deaths. LIMITATIONS: Animal study. CONCLUSION: Endoscopic pressure monitoring was reproducible, demonstrated the presence of gastric leak, and was as reliable as contrast-based radiographic leak testing.