Section Slides Research Articles

Preanalytical Phase Tumor Contaminants in Intraoperative Margins From Transoral Robotic Surgeries.

Tumor contaminants were incidentally noted in frozen section margins of oropharyngeal squamous cell carcinoma. To estimate the frequency of tumor contaminants in frozen section slides of patients who underwent surgery for pharyngeal cancer, and to characterize the surgical and pathologic context of these incidents. A retrospective search was conducted to identify pharyngeal resections from 2016 to 2022. Surgical pathology, operative reports, and frozen section slides were reviewed. Preanalytical phase tumor contaminants were defined as tumor contaminants that occurred in frozen section slides with or without occurrence in permanent slides. Eighty-one pharyngeal resections with intraoperative tumor bed margins for squamous cell carcinoma were identified. These included 308 tumor bed margins represented in 641 slides. Preanalytical contaminants occurred among 9 patients (11.1% of all and 21.4% of robotic surgeries) and in 3.8% of the 308 intraoperative tumor bed margins. A statistically significant association was found between contaminants and larger tumor size (Student t test, P = .04) and surgical approach (robotic versus open oropharyngectomy: Fisher exact test, P < .001). All patients with contaminants had intraoperative tumor disruption. Two frozen section deferrals (0.6%) and 2 discrepancies with final diagnosis (0.6%) attributed to contaminants were identified; however, clinical or surgical management was not affected in any patient. Preanalytical contaminants may cause confusion in intraoperative margin assessment. They are more likely to occur in margins of nonkeratinizing squamous cell carcinoma resected by transoral robotic surgery if there is intraoperative tumor disruption. Rarely, preanalytical contaminants lead to frozen section deferral or discrepancy with final diagnosis.

Prognostic Impact and Genomic Backgrounds of Renal Parenchymal Infiltration or Micronodular Spread in Nonmetastatic Clear Cell Renal Cell Carcinoma

A subset of clear cell renal cell carcinomas (ccRCCs) exhibits various growth patterns that infiltrate the normal renal parenchyma; however, our understanding of its association with cancer aggressiveness is incomplete. Here, we show that the morphology of the tumor interface with normal renal parenchyma is robustly associated with cancer recurrence after surgery, even when compared with the TNM staging system or the World Health Organization/International Society of Urological Pathology (WHO/ISUP) nuclear grade in nonmetastatic ccRCC. Hematoxylin and eosin–stained slides of whole tissue sections from surgical specimens were analyzed using a cohort of 331 patients with nonmetastatic ccRCC treated with radical nephrectomy. The patients were classified into 10 subgroups based on our classification algorithms for assessing the tumor interface with normal renal parenchyma. Among the 10 subgroups, 4 subgroups consisting of 40 patients (12%) were identified to have aggressive forms of nonmetastatic ccRCC associated with poor prognosis and unified as renal parenchymal infiltration or micronodular spread (RPI/MNS) phenotypes. Multivariable analyses showed that RPI/MNS phenotypes were robustly associated with shorter disease-free survival, independently of existing pathological factors including the TNM staging system and WHO/ISUP nuclear grade. The hazard ratio was highest for RPI/MNS (4.62), followed by WHO/ISUP grades 3 to 4 (2.11) and ≥pT3a stage (2.05). In addition, we conducted genomic analyses using next-generation sequencing of infiltrative lesions in 18 patients with RPI/MNS and tumor lesions in 33 patients without RPI/MNS. Results showed that alterations in SETD2 and TSC1 might be associated with RPI/MNS phenotypes, whereas alterations in PBRM1 might be associated with non-RPI/MNS phenotypes. These data suggest that RPI/MNS may be associated with aggressive genomic backgrounds of ccRCC, although more comprehensive analyses with a larger sample size are required. Future studies may further elucidate the clinical implications of RPI/MNS, particularly for deciding the indication of adjuvant treatment after nephrectomy.

WOOD ANATOMY INDICES AND REVEGETATION POTENTIALS OF THREE TAXA OF THE EUPHORBIACEAE

The suitability of three plant taxa namely: Bridelia ferruginea, Hura crepitans and Ricinodendron heudelotii as potential revegetation plants in desertified areas were assessed using Calquist’s wood anatomy indices (vulnerability and mesomorphy) using an ecological survey design. Temporal and permanent slides of transverse sections were prepared and vessel length and diameter (µm) measured using a Motic B3 Compound Microscope and vessel density determined for each of the plant taxa. The observed high vulnerability and high mesomorphy index values in Hura crepitans and Ricinodendron heudelotii indicates that they did not fall within the required ranges of 0 – 2.5 and 0 – 99 for the two indices respectively and cannot adapt well in xeric areas. However, Bridelia ferruginea fell within the range. In conclusion, Hura crepitans and Ricinodendron heudelotii are mesophytes while Bridelia ferruginea was xerophytic and can flourish in xeric areas, therefore, it possesses a great revegetation potential.

Protocol for correlation of histological risk assessment/scoring system with a depth of invasion in oral squamous cell carcinoma.

The commonest type of cancer in the head and neck region is oral squamous cell carcinoma (OSCC) due to its high rates of occurrence and mortality. The early diagnosis of oral cancer gives better prognosis. Brandwein-Gensler criteria predict the early stage of OSCC cases with a high risk of locoregional recurrence. To correlate Brandwein-Gensler criteria and depth of invasion of OSCC with three-year survival. In the study, This study will include 80 random histopathologically-diagnosed cases of OSCC. hematoxylin-eosin (HE)-stained section slides will be used to evaluate, Brandwein and Gensler criteria by three histopathologists in a blinded manner. The depth of invasion assessment will be done from the basement-membrane (BM), in regions where the BM has been lost, as well as from an illustrative line connecting the BM from the neighbouring epithelium to the point of deepest tumour invasion in the connective-tissue stroma with the help of a research microscope (Leica-DMLB2) in resected tissue specimens of OSCC cases. The present study will find the correlation between Brandwein-Gensler criteria and depth of invasion in OSCC in order to evaluate the locoregional recurrence in OSCC cases. In high-risk OSCC cases, there may be an increased depth of invasion in resected tissues. We hypothesized that the correlation between Brandwein-Gensler criteria and depth of invasion can be used as an independent predictor for locoregional recurrence in OSCC.

Thoracic Frozen Section Pitfalls: Lung Adenocarcinoma Versus Selected Mimics.

Intraoperative (frozen section) analysis of lung lesions (nodules, masses, ground-glass opacities) can occasionally be diagnostically challenging. To describe selected pitfalls in thoracic frozen sections with a focus on the differential diagnosis between adenocarcinoma and its mimics, and to provide tips to prevent misinterpretation. Peer-reviewed literature and the author's experience. A common challenge in thoracic frozen sections is the differential diagnosis between lung adenocarcinoma and its mimics. Diagnostic difficulties arise because mimics of adenocarcinoma often entrap reactive lung epithelium that can appear atypical on frozen section slides. Entities that can be misinterpreted as adenocarcinoma include ciliated muconodular papillary tumor/bronchiolar adenoma, hamartoma, inflammatory myofibroblastic tumor, and pulmonary Langerhans cell histiocytosis. Knowledge of the key clinical, radiologic, and histologic features of these entities can help prevent overdiagnosis of adenocarcinoma. Pathologic findings that facilitate the distinction between adenocarcinoma and its mimics at frozen section include the appearance and contour of the lesion at low magnification, growth patterns, cilia, stromal features, shape of the epithelial cells (cuboidal versus columnar), nuclear features of malignancy (crowding, hyperchromasia, irregular contours), and abruptness of the junction between the lesion and adjacent uninvolved lung. Knowledge of the clinical context, imaging findings, and the surgical consequence of the intraoperative diagnosis can also prevent diagnostic errors. Finally, since adenocarcinomas of the lung are often relatively bland and lack the stromal desmoplasia seen in adenocarcinomas of other organs, familiarity with the morphologic spectrum of lung adenocarcinomas at frozen section analysis is important.

Role of SOX10 Immunohistochemical Expression in Diagnosing Triple Negative Breast Cancer and Its Correlation With Clinicopathological Features.

Triple-negative breast cancer (TNBC) poses a diagnostic challenge for histopathologists due to the reduced frequency of breast-specific markers. SOX10 has emerged as a useful diagnostic marker for TNBC. The aim of our study was to determine the frequency of SOX-10 immunohistochemical (IHC) expression in our cohort and assess its correlation with clinicopathological and histological features. We included 72 primary TNBC cases. Specimens includedtru-cut biopsies and excision specimens. We stained whole slide sections of these specimens with SOX10 antibody and calculated its frequency (%) of expression and H-score. We applied the chi-square test to assess the correlation between SOX10 expression and clinicopathological and histological features such as the patient's age, specimen type, tumor size, histological type, histological grade, nuclear pleomorphism, mitotic count, tumor-infiltrating lymphocytes (TILs), necrosis, calcification, lymphovascular invasion (LVI), lymph node involvement, T stage, and N stage. SOX10 expression was observed in 42 (58.3%) cases with a median H-score of 57.5. The expression was significantly higher in tru-cut biopsy specimens as compared to excision specimens (73.5 vs 41.7%) and TILsnegative tumors as compared to TILs positive tumors (64.3% vs 27.3). Metaplastic carcinoma showed reduced expression when compared with non-metaplastic tumors (35.7% vs 63.8%), but statistical significance was not achieved. No correlation was observed with the patient's age, tumor size, histological type, histological grade, nuclear pleomorphism, mitotic count, necrosis, calcification, LVI, lymph node involvement, T stage, and N stage. SOX10 was expressed in more than half of the TNBC cases of our study which not only highlights its diagnostic utility but advocated its application in combination with other breast-specific markers. The expression didn't correlate with the majority of clinicopathological and histological features, but correlation with tru-cut biopsy specimens and absence of TILs draws attention towards possible roles of proper fixation and host immunity, respectively.

The proportion of tumour stroma predicts response to treatment of immune checkpoint inhibitor in combination with chemotherapy in patients with stage IIIB-IV non-small cell lung cancer.

Immunotherapy has brought a new era to cancer treatment, yet we lack dependable predictors for its effectiveness. This study explores the predictive significance of intratumour stroma proportion (iTSP) for treatment success and prognosis in non-small cell lung cancer (NSCLC) patients undergoing treatment with immune check-point inhibitors (ICIs) together with chemotherapy. We retrospectively collected data from patients with unresectable stage IIIB-IV NSCLC who were treated with first-line ICIs and chemotherapy. Each patient received a confirmed pathological diagnosis, and the pathologist evaluated the iTSP on haematoxylin and eosin (H&E)-stained sections of diagnostic tissue slides. Among the 102 H&E-stained biopsy samples, 61 (59.8%) were categorised as stroma-L (less than 50% iTSP), while 41 (40.2%) were classified as stroma-H (more than 50% iTSP). We observed that the stroma-L group exhibited a significantly better objective response rate (ORR) (72.1 versus 51.2%, P = 0.031) and deeper response depth (DpR) (-50.49 ± 28.79% versus -35.83 ± 29.91%, P = 0.015) compared to the stroma-H group. Furthermore, the stroma-L group showed longer median progression-free survival (PFS) (9.6 versus 6.0 months, P = 0.011) and overall survival (OS) (24.0 versus 12.2 months, P = 0.001) compared to the stroma-H group. Multivariate Cox proportional hazards regression analysis indicated that iTSP was a highly significant prognostic factor for both PFS [hazard ratio (HR) = 1.713; P = 0.030] and OS (HR = 2.225; P = 0.003). Our findings indicate that a lower iTSP corresponds to improved clinical outcomes and greater DpR in individuals with stage IIIB-IV NSCLC treated with first-line ICIs and chemotherapy. The iTSP could potentially serve as a predictive biomarker for ICIs therapy response.

Abstract 5561: Whole slide Imaging Mass Cytometry allows the rapid profiling of the immune landscape of histopathologically aggressive prostate tumors

Abstract Patients with Gleason pattern 4 or 5 prostate tumors have a high risk of biochemical recurrence and worse survival. Affected by their local environment, dynamic immune cell phenotypes can both hinder or drive cancer progression. To understand the proteomic environments that facilitate specific immune cell responses and interactions in advanced prostate cancer, we have spatially resolved the immune cell content and metabolic features of Gleason pattern 4 and 5 and subpatterns of prostate tumors. To scale quantitative multiplexed histopathology measurements to human disease, we have applied a new high-throughput whole slide modality of high-plex Imaging Mass CytometryTM to simultaneously quantify immune cells, metabolic states, prostate specific pathways, and biomarkers in 125 whole slide sections from 42 patients over 100 cm2 of tissue. It is essential to image whole slide sections in order to fully evaluate the complete heterogeneity of these cancer samples. In parallel, multi-region macrodissection shotgun proteomics and both glycan and extracellular matrix MALDI imaging mass spectrometry have quantified the proteome associated with specific immune cell environments. Together, we identify localized proteomic microenvironments associated with specific tumor supportive or inhibitory immune cell content in human tumors that may help differentiate which high-risk patients will have a rapid biochemical recurrence following radical prostatectomy. Citation Format: Jennifer L. Gorman, Lydia Y. Liu, Jordan P. Hartig, Nikesh Parsotam, Amanda Khoo, Vladimir Ignatchenko, Sarah Asbury, Somi Afiuni, Ricardo Gonzalez, Michael J. Geuenich, Caitlin F. Harrigan, Yuju Lee, Jianan Chen, Liang Lim, Qanber Raza, Peggi M. Angel, Kieran Campbell, Stanley K. Liu, Michelle R. Downes, Richard R. Drake, Thomas Kislinger, David King, Hartland W. Jackson. Whole slide Imaging Mass Cytometry allows the rapid profiling of the immune landscape of histopathologically aggressive prostate tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5561.

Abstract 6183: Exploring the role of microenvironment context on diagnostic accuracy in tissue microarray core selection

Abstract Background: Tissue Microarrays (TMAs) stand to significantly improve the efficiency of multiplex spatial studies by including core samples taken from many tumor blocks in a single slide. However, as TMAs become increasingly prevalent, the implication of core selection within the tumor microenvironment (TME) on downstream discoveries is not well understood. This raises the question of which TME contexts are most predictive for scientific analyses. Methods: We segment whole tissue section (WTS) slides with a U-Net trained on pathologist annotations of tumor, DCIS, LCIS, normal, stromal, immune, and necrotic microenvironment contexts in 100 TCGA BRCA slides. We focus on 5-way PAM50 subtype prediction in breast cancer. We produce image embeddings for each core using a vision transformer pre-trained on histopathology images and use an attention-based aggregation model to predict PAM50 subtype. To evaluate the impact of core TME contexts in a held-out test set, we sample 0.6mm radius circular sections from 281 WTS images from 54 patients to produce one dataset of “majority non-cancerous” cores that the TME annotation model predicts as majority normal breast epithelial or necrotic tissue and one “majority cancerous” TMA dataset for the remaining cores. Results: We find that core microenvironment context directly influences diagnostic accuracy. Maximizing tumor content improves diagnostic accuracy on the PAM50 task, with the majority cancerous TMAs obtaining an AUROC of 0.80 (95% confidence interval 0.75-0.85), relative to 0.72 (95% CI 0.66-0.78) for majority non-cancerous TMAs and 0.82 (95% CI 0.80-0.84) for WTS images. Notably, our context-aware TMA sampling achieves accuracy within 2% of the WTS images, while poorly selected TMA cores underperform the WTS baseline by 10% on average. While TCGA is curated to contain patients with a very high tumor burden, and consequently random TMA selection performs well on this cohort (AUROC 0.77; 95% CI 0.74-0.79), our study indicates that tissue context is an important consideration when selecting cores from real donor tissue blocks. Our results demonstrate that TMA core sampling protocols should be informed by TME context to maximize analysis accuracy, and that intelligent core sampling can largely close the gap to WTS image accuracies on clinically-relevant tasks like PAM50 subtype prediction. These findings highlight the need for thoughtful TMA dataset construction and usage, especially as core selection becomes increasingly automated. We argue both for more targeted core selection from donor tissue blocks and for filtering of existing datasets. To avoid performance degradation, pipelines should identify and exclude these less task-relevant TMEs, where simulation serves as an efficient and task-specific approximation of TME context relevance. Citation Format: Addie Woicik, Zachary R. McCaw, Ben Dulken, insitro Research Team, Christopher Probert. Exploring the role of microenvironment context on diagnostic accuracy in tissue microarray core selection [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6183.

Research data in paleobotany: petrographic thin sections fossil wood dataset

Objective: This study was aimed at analyzing and disseminating the fossil wood collection data stored in the thin slide sections of the paleobotany collection of the Department of Paleontology and Stratigraphy of the Institute of Geosciences of a university in Southern Brazil. Thin sheets of petrified wood are described. Research data used in geosciences specifically seek to develop a model for the use of this type of sheet in paleobotany, enabling visualization of its representativeness in studies published over 40 years to obtain the anatomical characteristics of fossil woods and define their systematic affinities as a specific typology of research data in geosciences. Methods: The methodology involved interviewing a paleobotanical specialist and using different techniques applied in metric studies to map scientific production. Thus, a dataset of (20) thin slide sections of petrified fossil wood used in “Stressing environmental conditions in the “petrified forest” from the Mata Sequence in the Triassic context of the Paraná Basin,” a paper published by the Journal of South American Earth Sciences (DOI:10.1016/j.jsames.2023.104415), was used. Depending on the methodology, these thin petrified wood sheets can reveal paleoclimatic signatures based on the anatomical characteristics of the fossil wood. In addition to this case study, which represents a collection of more than (2.000) thousand blades of fossil wood and approximately 40 years of research, the paleobotanical collection of the department is reused in methodology classes. The collection comprises a database created by research physicists that provides information on anatomical features, systematic affinities, paleoclimatic conditions, and paleoenvironmental insights. Potential for reuse: The reuse, registration, storage, identification, and preservation of thin slide sections as a type of research data used in paleobotany aims to improve the methodology associated with the organization of the physical database of the institution. The research data and blades of fossil wood are being digitized, and soon will be available under the CC BY 4.0 license in the ZENODO repository, according to the sample described here in this data paper (DOI Mendeley:10.17632/b8phfcsync.1). Furthermore, the data can be reused in optical and electronic scanning microscopy software.

Abstract B064: Redefining phenotypic heterogeneity of pancreatic ductal adenocarcinoma: A bottom-up approach

Abstract Background: Pancreatic ductal adenocarcinoma (PDAC) tumor inter-patient heterogeneity has been well described with two major subtypes (classical and basal-like). An important intra-patient heterogeneity has not yet been extensively studied due to the lack of standardized and easily accessible high throughput methods compatible with clinical routine. Material and Methods: To build an immunohistochemical (IHC) tool capable of differentiating classical and basal-like tumors, relevant antibodies were selected using a multi-step process. The successive stages of an in-silico selection from the bulk transcriptome of 309 PDACs and 30 patient-derived xenografts followed by the validation on tissue microarrays in a cohort of PDAC (n=50) were conducted. We used our final IHC panel on whole slides of serial histology sections in 95 resected PDACs. After image registration, we performed a tile-based-analysis in tumoral and pre-neoplastic areas and a k-means clustering to identify relevant marker combinations. Results: Our final selection of the IHC panel included GATA6, CLN18, TFF1, MUC16, S100A2, KRT17, PanBasal. Among the 44,042 tumor tiles analyzed, 4 different phenotypes were identified: 1 classical (CLN18+, TFF1+, GATA6+), 1 intermediate (KRT17+) and 2 basal-like (MUC16+ vs S100A2+) with specific biological properties. A minor basal contingent drastically reduced overall survival (OS) in the multivariate analysis (HR=2.36, p=0.01). In contrast, the presence of the intermediate and classical clusters did not impact OS. However, among patients with PDAC expressing the classical cluster, a tremendous difference of OS was observed according to the co-occurence of a basal cluster (HR=0.34, p=0.003). These prognostic associations have been validated in an independent cohort of 150 patients with PDAC on tissue microarrays. By analyzing preneoplastic lesions, we showed the evolution process of pancreatic carcinogenesis going from a classical toward a basal through an early intermediate phenotype. Conclusion: Our restricted panel of antibodies could help pathologists to predict the high degree of PDAC heterogeneity, ultimately leading to an improvement of patient management. Citation Format: Marc Hilmi, Flore Delecourt, Jerôme Rafenne, Taib Bourega, Nelson Dusetti, Juan Iovanna, Yuna Blum, Magali Richard, Cindy Neuzillet, Anne Couvelard, Louis De Mestier, Vinciane Rebours, Rémy Nicolle, Jérôme Cros. Redefining phenotypic heterogeneity of pancreatic ductal adenocarcinoma: A bottom-up approach [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr B064.

A deep learning algorithm to detect cutaneous squamous cell carcinoma on frozen sections in Mohs micrographic surgery: A retrospective assessment.

Intraoperative margin analysis is crucial for the successful removal of cutaneous squamous cell carcinomas (cSCC). Artificial intelligence technologies (AI) have previously demonstrated potential for facilitating rapid and complete tumour removal using intraoperative margin assessment for basal cell carcinoma. However, the varied morphologies of cSCC present challenges for AI margin assessment. The aim of this study was to develop and evaluate the accuracy of an AI algorithm for real-time histologic margin analysis of cSCC. To do this, a retrospective cohort study was conducted using frozen cSCC section slides. These slides were scanned and annotated, delineating benign tissue structures, inflammation and tumour to develop an AI algorithm for real-time margin analysis. A convolutional neural network workflow was used to extract histomorphological features predictive of cSCC. This algorithm demonstrated proof of concept for identifying cSCC with high accuracy, highlighting the potential for integration of AI into the surgical workflow. Incorporation of AI algorithms may improve efficiency and completeness of real-time margin assessment for cSCC removal, particularly in cases of moderately and poorly differentiated tumours/neoplasms. Further algorithmic improvement incorporating surrounding tissue context is necessary to remain sensitive to the unique epidermal landscape of well-differentiated tumours, and to map tumours to their original anatomical position/orientation.

A Deep Learning-Based Approach to Estimate Paneth Cell Granule Area in Celiac Disease.

Changes in Paneth cell numbers can be associated with chronic inflammatory diseases of the gastrointestinal tract. So far, no consensus has been achieved on the number of Paneth cells and their relevance to celiac disease (CD). To compare crypt and Paneth cell granule areas between patients with CD and those without CD (non-CD) using an artificial intelligence-based solution. Hematoxylin-eosin-stained sections of duodenal biopsies from 349 patients at the McGill University Health Centre were analyzed. Of these, 185 had a history of CD and 164 were controls. Slides were digitized, and NoCodeSeg, a code-free workflow using open-source software (QuPath, DeepMIB), was implemented to train deep learning models to segment crypts and Paneth cell granules. The total area of the entire analyzed tissue, epithelium, crypts, and Paneth cell granules was documented for all slides, and comparisons were performed. A mean intersection-over-union score of 88.76% and 91.30% was achieved for crypt areas and Paneth cell granule segmentations, respectively. On normalization to total tissue area, the crypt to total tissue area in CD was increased and the Paneth cell granule area to total tissue area decreased when compared to non-CD controls. Crypt hyperplasia was confirmed in CD compared to non-CD controls. The area of Paneth cell granules, an indirect measure of Paneth cell function, decreased with increasing severity of CD. More importantly, our study analyzed complete hematoxylin-eosin slide sections using an efficient and easy to use coding-free artificial intelligence workflow.

Protocol for correlation of histological risk assessment/scoring system with a depth of invasion in oral squamous cell carcinoma

Introduction: The commonest type of cancer in the head and neck region is oral squamous cell carcinoma (OSCC) due to its high rates of occurrence and mortality. The early diagnosis of oral cancer gives better prognosis. Brandwein-Gensler criteria predict the early stage of OSCC cases with a high risk of locoregional recurrence. Objectives: To correlate Brandwein-Gensler criteria and depth of invasion of OSCC with three-year survival. Methodology: In the study, hematoxylin-eosin (HE)-stained section slides will be used to evaluate Brandwein and Gensler criteria and depth of invasion in resected tissue specimens of OSCC cases. Expected results: The present study will find the correlation between Brandwein-Gensler criteria and depth of invasion in OSCC in order to evaluate the locoregional recurrence in OSCC cases. In high-risk OSCC cases, there may be increased depth of invasion in resected tissues. Conclusions: We hypothesized that the correlation between Brandwein-Gensler criteria and depth of invasion can be used as an independent predictor for locoregional recurrence in OSCC.

Cytopathology of glioneuronal and neuronal tumours with histological correlations.

Glioneuronal and neuronal tumours constitute a diverse group of tumours that feature neuronal differentiation. In mixed glioneuronal tumours, a glial component is present in addition to the neuronal component. With a few exceptions (eg diffuse leptomeningeal glioneuronal tumour) they are well-circumscribed and slow-growing tumours, which is why their prognosis is intrinsically favourable after gross total resection. Rendering an intraoperative diagnosis of glioneuronal/neuronal tumour is therefore important-neurosurgeons should remove them to prevent the persistence of clinical symptoms and/or recurrence. In this context, cytopathological examination can be especially useful for assessing cellular details when frozen section artefacts render poor-quality preparations, as is the case for this group of tumours, which are frequently mistaken for infiltrating gliomas (eg diffuse astrocytoma infiltrating grey matter, oligodendroglioma) on frozen section slides. The aim of this article is to review the cytomorphological features of glioneuronal and neuronal tumours according to the 2021 World Health Organization classification of central nervous system tumours, 5th edition. Additionally, since interpretation in intraoperative cytology relies on intuiting tissue patterns from cytology preparations, representative histological figures of all discussed entities have been included. Clues for specific diagnoses and the primary diagnostic problems encountered during intraoperative procedures are also discussed.

Deep Learning Can Predict Bevacizumab Therapeutic Effect and Microsatellite Instability Directly from Histology in Epithelial Ovarian Cancer

Epithelial ovarian cancer (EOC) remains a significant cause of mortality among gynecologic cancers, with the majority of cases being diagnosed at an advanced stage. Before targeted therapies were available, EOC treatment relied largely on debulking surgery and platinum-based chemotherapy. Vascular endothelial growth factors have been identified as inducing tumor angiogenesis. According to several clinical trials, anti–vascular endothelial growth factor-targeted therapy with bevacizumab was effective in all phases of EOC treatment. However, there are currently no biomarkers accessible for regular therapeutic use despite the importance of patient selection. Microsatellite instability (MSI), caused by a deficiency of the DNA mismatch repair system, is a molecular abnormality observed in EOC associated with Lynch syndrome. Recent evidence suggests that angiogenesis and MSI are interconnected. Developing predictive biomarkers, which enable the selection of patients who might benefit from bevacizumab-targeted therapy or immunotherapy, is critical for realizing personalized precision medicine. In this study, we developed 2 improved deep learning methods that eliminate the need for laborious detailed image-wise annotations by pathologists and compared them with 3 state-of-the-art methods to not only predict the efficacy of bevacizumab in patients with EOC using mismatch repair protein immunostained tissue microarrays but also predict MSI status directly from histopathologic images. In prediction of therapeutic outcomes, the 2 proposed methods achieved excellent performance by obtaining the highest mean sensitivity and specificity score using MSH2 or MSH6 markers and outperformed 3 state-of-the-art deep learning methods. Moreover, both statistical analysis results, using Cox proportional hazards model analysis and Kaplan-Meier progression-free survival analysis, confirm that the 2 proposed methods successfully differentiate patients with positive therapeutic effects and lower cancer recurrence rates from patients experiencing disease progression after treatment (P < .01). In prediction of MSI status directly from histopathology images, our proposed method also achieved a decent performance in terms of mean sensitivity and specificity score even for imbalanced data sets for both internal validation using tissue microarrays from the local hospital and external validation using whole section slides from The Cancer Genome Atlas archive.

Clinical Characteristics of Chronic Rhinosinusitis With Nasal Polyp According to Histopathological Endotypes and Staining Method for Neutrophilic Polyp Classification and Its Clinical Implication

Background and Objectives There are various methods used to histologically assess the cell count of neutrophils in nasal polyps. With various classification of neutrophilic nasal polyps, determining the appropriate staining techniques and criteria is deemed important for the diagnosis of neutrophilic nasal polyps by assessing neutrophil cell counts. In this study, we tried to optimize different methods of neutrophil counting and staining by comparing clinical outcomes.Subjects and Method We studied 207 patients who underwent endoscopic sinus surgery for chronic rhinosinusitis with nasal polyp from August 2014 to September 2018. Patients’ nasal polyp were taken to make following three slide sections: hematoxylin and eosin, human neutrophil elastase (HNE), myeloperoxidase. After staining, microscope picture (×400) was taken and neutrophils were counted. Neutrophil polyp (NP) was classified either by the tissue neutrophil count (20/HPF) or by the neutrophil percentage (1%/total cell) for clinical outcome comparison.Results Two groups were made after HNE staining: the NP and the non-NP groups. The L-K scores and delta showed significant differences between each group while neutrophil was defined based on 20 counts/HPF (&lt;i&gt;p&lt;/i&gt;&lt;0.001). By Kaplan-Meier estimation, there was no statistical meaning between the two groups. But the NP group had a tendency to recur more than the non-NP group while 20 counts/HPF definition was used (&lt;i&gt;p&lt;/i&gt;&gt;0.05).Conclusion HNE staining and 20 counts/HPF were the most specific for neutrophil counting. Analyzing the nasal polyp into two groups due to histologic types showed that the NP group had worse prognosis than the non-NP group. In conclusion, neutrophils in the nasal polyp might be considered seriously for clinical outcomes.

Role of intraoperative touch imprint cytology and immunohistochemistry in the diagnosis of metastatic malignancies in the central nervous system: Cyto-histomorphological findings and differential diagnosis.

Brain metastases (BMs) are intracranial neoplasms that are more common in adults than primary brain tumors, causing significant mortality and morbidity in cancer patients. This study aimed to evaluate the definitive histopathological diagnosis using touch imprint cytology and the importance and use of immunohistochemistry in the diagnosis of primary origin. Cytological, paraffin section, and immunohistochemical study slides of all metastatic brain tumors consecutively consulted at the pathology department between 2018 and 2023 were evaluated. The sensitivity, specificity, and accuracy of patients' diagnostic results who underwent imprint cytology were compared based on the final diagnosis histopathological report. A total of 45 patients with and without intraoperative consultation were included in the study. The definitive histopathologic diagnosis and the diagnostic accuracy rate of imprint cytology for distinguishing glial and metastatic tumors on paraffin sections was 100%. Immunohistochemistry was performed in all patients (except one patient; immediate exitus) and histological classification of the primary tumor was performed by analysis of clinical findings and biomarkers. The primary origins of metastatic tumors were often lung and breast, with adenocarcinoma subtype histomorphology, cerebral hemispheres, and discrete foci of metastasis. TPs is a simple and rapid technique that supports diagnosis in intraoperative neuropathology and is a very cost-effective procedure. The pathologist's experience is the key factor in the diagnosis and reduces the need for a frozen section. In our series, the final histopathologic correlation of imprint cytology in the diagnosis of primary and metastatic tumors is 100%.

DS23 Efficiency and performance of slide stainers during Mohs frozen section processing

Abstract Mohs micrographic surgery (MMS) relies on good-quality, well-stained frozen sections for effective histological analysis. Slides should also be produced as quickly as possible. Automation of complementary devices in the laboratory ensures standardization and efficiency and improves the overall quality of performance. Our study evaluated the efficiency and performance of the Autostainer-XL (Leica) vs. the Linistat (Thermo Scientific) slide stainer within a busy MMS unit. The Autostainer-XL rapidly dries, loads and unloads slides automatically allowing the Mohs-trained biomedical scientist (BMS) to work in parallel on cryotomy. The Autostainer-XL stains slides with haematoxylin and eosin within 10 min and 50 s. In comparison, the Linistat was much slower and required the Mohs-trained BMS to fix the slides manually on a hotplate, place them in industrial methylated spirit, wash them in water and load individual slides into the Linistat, taking 16 min and 45 s to complete the staining process. Two blinded assessors retrospectively reviewed the same set of 50 Linistat-stained and 50 Autostainer-XL stained frozen section slides for consistency in staining. The scoring criteria were based on the modified UK National External Quality Assessment Service (NEQAS) Cellular Pathology Technique Mohs scheme assessment criteria. Each assessor allocated scores between 1 and 5 based on the scoring criteria. The mean quality scores were significantly higher for the Autostainer-XL compared with the Linistat (P &amp;lt; 0.05). In our MMS unit, up to 12 patients undergo MMS daily with an average of seven slides required per patient at the first stage, leading to a high processing burden within the Mohs laboratory, particularly at the first stage. The Autostainer-XL increased productivity, with the ability to load 30 slides per rack, while the Linistat was only able to load six slides per rack. In practice, within our MMS unit, the Autostainer-XL reduced the time taken to produce all slides at the first layer by more than 1 h when compared with the Linistat slide stainer. When surveyed, 100% (n = 8/8) of Mohs-trained BMS in the laboratory preferred the Autostainer-XL than the Linistat, with comments suggesting that it was easy to use, quick, precise and an important device that can withstand the demands of a busy Mohs laboratory. The Autostainer-XL offers improved efficiency and performance, with reduced staining times, an ability to process a larger number of slides and fully customisable automation when compared with the Linistat (Thermo Scientific) slide stainer.

DS24 Prospective study comparing ex vivo confocal laser scanning microscopy and frozen section histopathology of 23 basal cell carcinomas treated with Mohs micrographic surgery

Abstract Ex vivo confocal laser scanning microscopy (CLSM) is an emerging technique that is used for the rapid analysis of freshly excised tissue during Mohs micrographic surgery (MMS). Previous studies on fluorescence CLSM have shown 88% and 99% sensitivity and specificity, respectively, of diagnosing basal cell carcinomas (BCCs) vs. conventional histology. The fourth-generation Vivascope 2500 allows fresh tissue to be scanned after minimal preparation with acetic acid and acridine orange, creating digitally coloured mosaic images, mimicking conventional histological haematoxylin and eosin slides. The scanning speed of &amp;lt; 3 min creates the potential to improve patient experiences, allowing multiple stages and repair in a single session, reducing overall operating times and improving efficiency. After a 2018 pilot study on a limited case series, we have begun the process of testing the real-world use of this technology. We present an initial prospective case series to assess BCC excision of stage 1 Mohs specimens using the Vivascope 2500 vs. conventional frozen section histology. Caldicot approval was sought. Over a 3-month period, 23 cases of stage 1 facial BCCs on one Mohs list were processed. Samples were obtained as standard bevelled Mohs excisions, and Mohs maps were created for all cases. There were three false-negative BCCs, of which two were infiltrative BCCs with small foci missed on the initial review on CLSM images and one superficial BCC not visible due to lack of epidermal capture. Of the four false-positive cases, the foci appearing to be BCC included inflammation in one, follicular structures in two and conjunctival glands misinterpreted as BCC in one eyelid case. Time taken to process specimens and read the digital images by CLSM was compared with the time taken to obtain and read frozen section slides. The shortest time recorded for CLSM and frozen sections was 6 min and 31 min, respectively. The longest time recorded for CLSM and frozen sections was 20 min and 57 min, respectively. In summary, CLSM shows promise in MMS for selected BCCs. Improved techniques to flatten the epidermis for better visualization and further experience with image reading and interpretation have the potential to minimize errors.