Faculty Bibliography

Introduction: SARS-CoV-2 (COVID-19) is known to cause severe respiratory infections with occasional accompanying pleural (PE), pericardial (PCE) or peritoneal effusion (PTE). The effect of COVID-19 disease on effusion cytology is not yet known. Therefore, our study aims to examine the cytomorphologic features and work-up of effusion fluid in patients in recovery from COVID-19 infection versus those with active disease.
Material(s) and Method(s): PE (n=15), PCE (n=1), PTE (n=19) samples from hospitalized patients with COVID-19 infection (6/1/2020-12/30/2020) were reviewed. EFs with metastatic carcinoma were excluded. Differential cell count (DCC), cytomorphology, and immunostains of EFs were retrospectively evaluated by a board-certified cytopathologist and compared between patients with active infection (AI, n=22, positive COVID-19 nucleic acid amplification test (NAAT) within 2 months) and recovery phase from COVID-19 (RC, n=13, negative COVID-19 NAAT for >2 months).
Result(s): Cytology diagnoses were: negative for malignancy (n=30), atypical (n=4), suspicious for malignancy (n=1). AI cases showed more atypical mesothelial cells than RC cases (Table 1, p<0.05), some with enlarged nuclei with prominent nucleoli and occasional multi-nucleation (Figure 1), and some with bizarre nuclei (Table 1, p<0.01). Immunostains were performed more often in AI than RC cases (50.0% vs 7.7%, p<0.05). DCC (available in 28 cases) showed no significant difference amongst AI and RC cases (Figure 1, p>0.05).
Conclusion(s): Our study found atypical and bizarre mesothelial cells to be present more often in effusions of cases with active COVID-19 infection than in samples from patients in recovery, though DCCs did not show significant difference. Diagnosis of malignancy may be considered in cases with such nuclear atypia, which explains increased immunostain work-up in AI cases. It is important for cytopathologists to consider the patients' COVID-19 infection status when evaluating effusion cytology cases. [Formula presented] [Formula presented] [Formula presented]
Copyright

BACKGROUND:The diagnosis of congenital toxoplasmosis can be inconclusive in many cases. Despite the several serological tests developed, the literature on biomarkers that can assist in the diagnosis of congenital an acute toxoplasmosis is limited. The objective of this study was to analyze the immunoreactive profile of Toxoplasma gondii protein bands with the potential to be biomarkers for diagnosis and prognosis of congenital and acute toxoplasmosis. METHODS:Peripheral blood samples from women of childbearing age and/or pregnant women diagnosed with acquired toxoplasmosis as well as from congenitally infected children were selected and submitted to immunoblotting for analysis of the immunoreactive bands profile by immunoglobulin G (IgG) antibodies. RESULTS:When comparing the immunoreactive bands profile for antibodies present in samples from different groups and subgroups, the 150, 18.5, and 16.96-kDa bands were more immunoreactive with the antibodies present in serum samples from the acquired infection group. The 343, 189, 150, 75, and 42-kDa bands showed more chance to be detected by the symptomatic congenital infection subgroup samples, while the 61, 50, and 16.96-kDa bands were significantly immunoreactive with the acute infection subgroup samples. CONCLUSIONS:The identification of these potential biomarkers can assist in early diagnosis and treatment of congenital toxoplasmosis.

BACKGROUND:Current interstitial lung disease (ILD) diagnostic guidelines assess criteria across clinical, radiologic and pathologic domains. Significant interobserver variation in histopathologic evaluation has previously been shown but the specific source of these discrepancies is poorly documented. We sought to document specific areas of difficulty and develop improved criteria that would reduce overall interobserver variation. METHODS:Using an internet-based approach, we reviewed selected images of specific diagnostic features of ILD histopathology and whole slide images of fibrotic ILD. After an initial round of review, we confirmed the presence of interobserver variation among our group. We then developed refined criteria and reviewed a second set of cases. RESULTS:The initial round reproduced the existing literature on interobserver variation in diagnosis of ILD. Cases which were pre-selected as inconsistent with usual interstitial pneumonia/idiopathic pulmonary fibrosis (UIP/IPF) were confirmed as such by multi-observer review. Cases which were thought to be in the spectrum of chronic fibrotic ILD for which UIP/IPF were in the differential showed marked variation in nearly all aspects of ILD evaluation including extent of inflammation and extent and pattern of fibrosis. A proposed set of more explicit criteria had only modest effects on this outcome. While we were only modestly successful in reducing interobserver variation, we did identify specific reasons that current histopathologic criteria of fibrotic ILD are not well defined in practice. CONCLUSIONS:Any additional classification scheme must address interobserver variation in histopathologic diagnosis of fibrotic ILD order to remain clinically relevant. Improvements to tissue-based diagnostics may require substantial resources such as larger datasets or novel technologies to improve reproducibility. Benchmarks should be established for expected outcomes among clinically defined subgroups as a quality metric.

Lung transplant is increasingly performed for the treatment of end-stage lung disease. As the number of lung transplants and transplant centers continues to rise, radiologists will more frequently participate in the care of patients undergoing lung transplant, both before and after transplant. Potential donors and recipients undergo chest radiography and CT as part of their pretransplant assessment to evaluate for contraindications to transplant and to aid in surgical planning. After transplant, recipients undergo imaging during the postoperative hospitalization and also in the long-term outpatient setting. Radiologists encounter a wide variety of conditions leading to end-stage lung disease and a myriad of posttransplant complications, some of which are unique to lung transplantation. Familiarity with these pathologic conditions, including their imaging findings and their temporal relationship to the transplant, is crucial to accurate radiologic interpretation. Knowledge of the surgical techniques and expected postoperative appearance prevents confusing normal posttransplant imaging findings with complications. A basic understanding of the indications, contraindications, and surgical considerations of lung transplant aids in imaging interpretation and protocoling and also facilitates communication between radiologists and transplant physicians. Despite medical and surgical advances over the past several decades, lung transplant recipients currently have an average posttransplant life expectancy of only 6.7 years. As members of the transplant team, radiologists can help maximize patient survival and hopefully increase posttransplant life expectancy and quality of life in the coming decades. ^©RSNA, 2021 An invited commentary by Bierhals is available online. Online supplemental material is available for this article.

Diffuse malignant mesothelioma (MM) is an incurable tumour of the serosal membranes, which is often caused by exposure to asbestos and commonly diagnosed at advanced stage. Malignant mesothelioma in situ (MMIS) is now included as diagnostic category by the World Health Organization (WHO). However, our international survey of 34 pulmonary pathologists with an interest in MM diagnosis highlights inconsistency regarding how the diagnosis is being made by experts, despite published guidelines. Whilst the WHO restricts the diagnosis to surgical samples, the very concept has implication for cytological diagnosis, which is already regarded as controversial in itself by some. MMIS is currently only applicable as precursor to MM with an epithelioid component, and raises the possibility for different molecular pathways for different histological MM subtypes. The clinical implications of MMIS at this stage are uncertain, but aggressive therapies are being initiated in some instances. Based on the results of the survey we here present a critical appraisal of the concept, its clinical and conceptual implications and provide practice suggestions for diagnosis. A low threshold for ancillary testing is suggested. The designations of 'malignant mesothelioma, cannot exclude MMIS' or 'atypical mesothelial proliferation with molecular indicators of malignancy, so-called MMIS' could be used on cytology samples, adding 'no evidence of invasion in sample provided' for surgical samples. Clinical and radiological correlation are integral to diagnosis and best done at multidisciplinary meetings. Finally, collaborative studies are required to improve our understanding of MMIS.

OBJECTIVES/OBJECTIVE:To describe the histologic features that are helpful in the diagnosis of the rare bronchiolar adenomas/ciliated muconodular papillary tumors (BAs/CMPTs) during intraoperative consultation. METHODS:Multi-institutional retrospective review of frozen sections of 18 BAs/CMPTs. RESULTS:In 14 of 18 cases, BA/CMPT was the primary reason for sublobar lung resection, and in 4 cases, BA/CMPT was an incidental finding intraoperatively for resections performed for carcinoma in other lobes. There were 11 proximal-type/classic BAs/CMPTs and 7 distal-type/nonclassic BAs/CMPTs. Only 3 (16.7%) of 18 were correctly diagnosed at the time of frozen section, all of which were proximal type/classic. The remainder were diagnosed as adenocarcinoma (n = 7); invasive mucinous adenocarcinoma (n = 1); non-small cell lung carcinoma (n = 1); cystic mucinous neoplasm, favor adenocarcinoma (either mucinous or colloid type) (n = 1); favor adenocarcinoma, cannot exclude CMPT (n = 1); atypical proliferation (n = 2); mucinous epithelial proliferation (n = 1); and mucous gland adenoma (n = 1). CONCLUSIONS:BA/CMPT can potentially be misdiagnosed as carcinoma during intraoperative consultation. On retrospective review of the frozen sections, the presence of the following may help to avoid misdiagnosis: a mixture of bland ciliated columnar cells, mucinous cells, and, most important, a basal cell layer, as well as a lack of necrosis, significant atypia, and mitoses.

The ongoing pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is currently affecting millions of lives worldwide. Large retrospective studies indicate that an elevated level of inflammatory cytokines and pro-inflammatory factors are associated with both increased disease severity and mortality. Here, using multidimensional epigenetic, transcriptional, in vitro, and in vivo analyses, we report that topoisomerase 1 (TOP1) inhibition suppresses lethal inflammation induced by SARS-CoV-2. Therapeutic treatment with two doses of topotecan (TPT), an FDA-approved TOP1 inhibitor, suppresses infection-induced inflammation in hamsters. TPT treatment as late as 4 days post-infection reduces morbidity and rescues mortality in a transgenic mouse model. These results support the potential of TOP1 inhibition as an effective host-directed therapy against severe SARS-CoV-2 infection. TPT and its derivatives are inexpensive clinical-grade inhibitors available in most countries. Clinical trials are needed to evaluate the efficacy of repurposing TOP1 inhibitors for severe coronavirus disease 2019 (COVID-19) in humans.

Rationale:Malignant pleural mesothelioma(MPM) has a poor prognosis with median survival of 12-24 months. We are not aware of prior studies examining the immune microenvironment in tumor draining lymph nodes (TDLN) in MPM. Our aim is to compare the tumor microenvironment(TME) and the microenvironment of TDLN. We hypothesize that the TME will display an immunosuppressive phenotype reflected in the TDLN.
Method(s):We performed digital spatial profiling(DSP) using the GeoMx (NanoString) platform on stored primary tumor and nodal biopsy specimens from 3 patients from our tumor bank. Samples from both primary tumor and lymph nodes were sectioned and labeled with pancytokeratin (CK). Tissue was then classified as "tumor" or "nontumor" using semi-automated segmentation based on pan-Cytokeratin (panK) labeling. The slides were then labeled with antibodies to 58 selected markers, with each unique antibody attached to a respective oligonucleotide. The tissue was exposed to UV light separately for tumor and non-tumor regions, cleaving the oligonucleotides from the attached antibodies. The oligonucleotides from the separate tumor and non-tumor regions were quantified using nCounter (NanoString).
Result(s):The non-neoplastic regions of the primary tumor contained higher expression of proteins associated with inflammatory cells including helper T-cells, cytotoxic T-cells, B-cells, macrophages, neutrophils, natural killer cells(Table 1). Furthermore, there was greater expression of immune checkpoint proteins, PD-L1 and CTLA-4, and CD163 and CD14, proteins associated with immunosuppressive macrophages, in the non-neoplastic region compared to the neoplastic region of the tumoe(Table 1). TDLNs contained similar levels of expression of lymphocyte markers, including those delineating cytotoxic T-cells and helper T-cells, as the primary tumor(Table 1). Despite this, TME expressed higher levels of T-cell exhaustion and immunsupression markers (FOXP3, LAG3, PD-1, CTLA-4) than TDLN(Table 1).
Conclusion(s):DSP is feasible in Formalin-fixed paraffin embedded (FFPE) mesothelioma specimens, providing a method for using quantitative immunopathology to study corresponding immune microenvironments. In our study, the non-tumor region of the primary tumor contained macrophages, lymphocytes, natural killer cells, and cancer-associated fibroblasts consistent with prior descriptions of the mesothelioma TME. Increased expression of immune checkpoint molecules in the non-tumor region suggests an immunosuppressive TME. TDLNs demonstrated similar lymphocyte markers, but without corresponding immune checkpoint expression of t suggesting the immunosuppressive phenotype of the TME may not be reflected in TDLNs. This pilot study is the first to use DSP to preliminarily characterize TDLNs in mesothelioma. We plan to apply this approach to stored additional MPM and NSCLC specimens to gain an in-depth understanding of the relationship between TME and TDLN

INTRODUCTION:Programmed death-ligand 1 (PD-L1) immunohistochemistry (IHC) is required to determine the eligibility for pembrolizumab monotherapy in advanced NSCLC worldwide and for several other indications depending on the country. Four assays have been approved/ Communauté Européene-In vitro Diagnostic (CV-IVD)-marked, but PD-L1 IHC seems diversely implemented across regions and laboratories with the application of laboratory-developed tests (LDTs). METHOD:To assess the practice of PD-L1 IHC and identify issues and disparities, the International Association for the Study of Lung Cancer Pathology Committee conducted a global survey for pathologists from January to May 2019, comprising multiple questions on preanalytical, analytical, and postanalytical conditions. RESULT:A total of 344 pathologists from 64 countries participated with 41% from Europe, 24% from North America, and 18% from Asia. Besides biopsies and resections, cellblocks were used by 75% of the participants and smears by 11%. The clone 22C3 was most often used (69%) followed by SP263 (51%). They were applied as an LDT by 40% and 30% of the users, respectively, and 76% of the participants developed at least one LDT. Half of the participants reported a turnaround time of less than or equal to 2 days, whereas 13% reported that of greater than or equal to 5 days. In addition, quality assurance (QA), formal training for scoring, and standardized reporting were not implemented by 18%, 16%, and 14% of the participants, respectively. CONCLUSIONS:Heterogeneity in PD-L1 testing is marked across regions and laboratories in terms of antibody clones, IHC assays, samples, turnaround times, and QA measures. The lack of QA, formal training, and standardized reporting stated by a considerable minority identifies a need for additional QA measures and training opportunities.