Routine Pathology Practice Research Articles

Routine Elastic Staining Helps Detection of Vascular Invasion in Colorectal Cancer: A Comprehensive Analysis of T3 or Higher Tumors Without Lymph Node Metastasis.

Vascular invasion (VI) in colorectal carcinoma (CRC) is an independent prognostic feature and a high-risk indicator for adjuvant chemotherapy in stage II CRC. This study evaluated the effect of elastic staining on VI detection. The VI was assessed using elastic staining in 154 patients with CRC. Based on hematoxylin and eosin (H&E) staining, cases were classified into three groups: absent (n=80), equivocal (n=23), and suspected (n=51). Two sections per case were evaluated for VI using elastic staining, and the presence of VI on one or both slides was confirmed. Finally, the correlation between the VI and other clinicopathological factors was analyzed. The overall detection rate of VI using elastic staining was 67/154 (51.4%). VI was detected in 17/80 (21.3%), 3/23 (13.0 %), and 47/51 (92.2%) patients in the absent, equivocal, and suspected groups, respectively. VI was detected in both sections of the elastic staining slides in 28 cases, and in only one section in 38 cases. The VI was significantly associated with perineural invasion, M stage, and synchronous metastasis. VI detection using H&E staining alone is not reliable, emphasizing the importance of elastic staining in improving VI detection. Therefore, we recommend the incorporation of elastic staining into routine pathological practice for all pT3 and pT4 CRC cases.

The implementation of molecular tumor profiling in the practice of pediatric cancer pathology: The pathologists' experience.

The increased accessibility and utilization of molecular testing including next-generation sequencing (NGS) has impacted the practice of pediatric pathology, with diagnostic, prognostic, and therapeutic implications for our patients. This survey is the first to describe the utilization of molecular testing in the routine practice of pediatric pathology for the care of children with known or suspected solid tumors. The Society for Pediatric Pathology Practice Committee distributed a survey to our membership asking 25 questions about training, practice setting, molecular ordering practices, and barriers to testing. Seventy-five pathologists responded to the survey. The survey provides valuable insight into the current use of molecular testing for the care of children with known or suspected solid tumors. Most respondents reported that they are increasingly using a variety of molecular techniques, with increased use over time, and that NGS is useful. These results highlight a variety of barriers to molecular testing, including cost, insurance coverage, turnaround time, limitations of available assays (including limited coverage of pediatric-specific alterations), and difficulty in determining the most appropriate test to order. These data may be useful in supporting pediatric pathologists in their practice.

New clinicopathological concept of endometrial carcinoma with integration of histological features and molecular profiles.

The dual-stratified pathway of endometrial carcinomas (ECs) has long been dominant. However, in 2013, The Cancer Genome Atlas (TCGA) defined four EC subgroups with distinctive prognoses. Inspired by TCGA, in 2018, the Proactive Molecular Risk Classifier for Endometrial Cancer (ProMisE) provided four pragmatic molecular classifiers to apply surrogate immunohistochemical markers to TCGA subgroup categorization. These trends prompted the revision of 2020 WHO Classification of Female Genital Tumors, 5th edition (2020 WHO classification), in which four molecular subtypes are recognized: POLE-ultramutated; mismatch repair-deficient; p53-mutant; and no specific molecular profile. In the 2020 WHO classification, the diagnostic algorithm is characterized by prioritizing POLEmut over other molecular abnormalities. Following the 2020 WHO classification, Federation of International Gynecology and Obstetrics (FIGO) proposed a new staging system in 2023. The updated system focuses on diagnostic parameters, such as histological type and grade, lymphovascular space invasion, and molecular alterations. These new histomolecular diagnostic concepts of ECs are being accordingly introduced into the routine pathology practice. For the first time, the 2020 WHO classification includes mesonephric-like adenocarcinoma (MLA) as a novel histological entity, mimicking the conventional mesonephric adenocarcinoma, but is considered of Müllerian ductal origin.

Prognostic role of tumor budding in oral squamous cell carcinoma: a retrospective study

Background Tumor budding is defined as a single cell or a cluster of up to five tumor cells at the invasion front of all oral squamous cell carcinoma (OSCC) cases. Tumor budding is considered as a marker of many important events in oral carcinoma, including the epithelial-mesenchymal transition, invasion, metastasis, and for further prognosis. Methods A total of 30 clinically and histopathologically diagnosed cases of OSCC were retrieved from the archival of the Department of Oral Pathology and Microbiology. After assessing the sections for the presence of tumor budding (TB), it is further categorized into high-intensity TB and low-intensity TB. Results We found a strong association between lymph node metastasis and histopathological grading in the current study. There was no association between TB and a patient’s survival rate. Conclusions This study emphasizes the significance of tumor budding, its relevance to prognosis, and reproducibility, as well as the significance of its evaluation and incorporation into routine surgical pathology practice in the management of OSCC. As a result, we believe that tumor budding is a crucial factor in determining tumor behavior.

Prevalence of human papillomavirus in oral cancer in Asia: A systematic review and meta-analysis.

To determine the prevalence of human papillomavirus (HPV) in oral squamous cell carcinoma (OSCC) across Asian countries, focusing on South and Southeast Asia. A systematic search of four databases-MEDLINE/PubMed, EMBASE, Scopus, and ProQuest-was conducted to identify observational studies published between January 2013 and December 2023. The pooled prevalence of HPV was estimated using random-effects models, and subgroup analysis was performed to investigate the source of heterogeneity. A total of 77 studies were included, comprising 7289 OSCC cases from 11 countries. The pooled HPV prevalence in OSCC was 23.1% (95% CI 17.9-28.7, I2 = 96.7%). South Asia had the highest prevalence (27.1%), followed by East Asia (19.4%), and Southeast Asia (16.7%). Two subtypes were commonly reported: HPV-16 (9.1%) and HPV-18 (5.1%). Anatomical subsites, buccal mucosa (34.0%), and floor of the mouth (33.2%) had similar ranges of HPV prevalence. All studies exhibited a high degree of heterogeneity, with the OSCC location and risk of bias identified as potential sources of heterogeneity. Due to the high HPV prevalence in OSCC in Asia, HPV detection in routine pathology practice is recommended. Future studies should be conducted in multicentre settings using similar HPV detection methods and reporting detailed demographic and clinical information on oral sub-sites.

Microscopic Growth Pattern of Metastatic Colorectal Carcinomas, Morphological Findings of the Non-Neoplastic Liver, andTheir Relationship With Prognosis and Survival.

Introduction. Various clinicopathological, radiological, and molecular parameters are predictive of prognosis in patients with colorectal carcinoma and distant organ metastases continue to have a significant place among them. Recent studies reveal that not only the presence of metastases but also the histopathological growth pattern of the metastatic tumor significantly affects prognosis. This study aimed to investigate the prognostic significance of the histopathological growth patterns of metastatic tumors, the morphological findings in the peritumoral non-neoplastic liver, and its relationship with survival in patients who have metastatic colorectal carcinoma. Materials and Method. Hematoxylin and eosin-stained slides of the tumors were re-examined in terms of histopathological diagnosis, growth pattern, presence and degree of peritumoral lymphocytic infiltration, steatosis, cholestasis, and peritumoral ductular reaction in the non-neoplastic liver. Results. In terms of histopathological growth patterns, 24 (47%) tumors showed replacement, 19 (37%) showed desmoplastic and 8 (16%) showed pushing growth pattern. In terms of total survival, there was a significant difference (P = .011) between desmoplastic and replacement growth patterns, and the survival period was shorter in patients with replacement growth patterns. Conclusion. Recent studies show that histopathological growth patterns in metastatic liver tumors may be a promising prognostic and predictive parameter. It is important to include this parameter in the pathology reports as it does not require additional equipment for evaluation in routine pathology practice, does not bring additional costs, or takes a long time to evaluate. This feature can be evaluated standardly by every pathologist.

Role of Cytology for Diagnosis of Appendageal Tumours and Comparison with Histopathology: A Cross-sectional Study

Introduction: Skin adnexal neoplasms are quite rare in routine pathology practice, yet the domain of Fine Needle Aspiration Cytology (FNAC) remains relatively unexplored. This current study explored different Adnexal Tumours (ATs) through FNAC, emphasising the efficacy of cytological diagnosis as a safe, simple, quick, and cost-effective tool with high sensitivity and specificity for diagnosing skin ATs. Aim: To diagnose various appendageal tumours through cytological examination, confirm and categorise them (benign/ malignant) via histopathological examination, and identify any cytohistological discrepancies. Materials and Methods: This retrospective cross-sectional study was conducted over a five-year period (January 2016- December 2021) at the Department of Pathology, Nil Ratan Sircar Medical College and Hospital (NRSMCH) in Kolkata, West Bengal, India, following ethical approval. Patients underwent history and physical examination followed by FNAC. ATs were diagnosed cytologically in 78 out of 23,852 FNAC cases. The results were compared with histopathological diagnosis to assess concordance or discordance based on predefined criteria. Leishman-Giemsa (L&G) stain was used for cytological examination, and Haematoxylin and Eosin (H&E) stain for histopathology. Results: Cytologically, ATs were diagnosed in 78 cases (0.33%), with the majority being benign 69 (88.46%). There was a female preponderance (49, 62.82%) with a male-to-female ratio of 1:1.7. Nodular Hidradenoma (NH) was the most common diagnosis (16/48=33.33%). Out of 59 biopsy-confirmed lesions, 55 showed cytohistological concordance (93.22%), with only four discordant cases (6.78%). The sensitivity, specificity, positive predictive value, and negative predictive value for detecting malignancy in this series were 70%, 97.90%, 87.50%, and 94.10%, respectively. Conclusion: FNAC should be the primary choice for detecting skin ATs due to its safety, reliability, high predictive value, and low chance of discordance. Although occasional cytohistological discrepancies may occur, proper clinical correlation, aspiration from multiple sites, expert cytopathologists, and high-quality staining are essential to avoid misdiagnosis.

Optimized whole-genome sequencing workflow for tumor diagnostics in routine pathology practice.

Two decades after the genomics revolution, oncology is rapidly transforming into a genome-driven discipline, yet routine cancer diagnostics is still mainly microscopy based, except for tumor type-specific predictive molecular tests. Pathology laboratories struggle to quickly validate and adopt biomarkers identified by genomics studies of new targeted therapies. Consequently, clinical implementation of newly approved biomarkers suffers substantial delays, leading to unequal patient access to these therapies. Whole-genome sequencing (WGS) can successfully address these challenges by providing a stable molecular diagnostic platform that allows detection of a multitude of genomic alterations in a single cost-efficient assay and facilitating rapid implementation, as well as by the development of new genomic biomarkers. Recently, the Whole-genome sequencing Implementation in standard Diagnostics for Every cancer patient (WIDE) study demonstrated that WGS is a feasible and clinically valid technique in routine clinical practice with a turnaround time of 11 workdays. As a result, WGS was successfully implemented at the Netherlands Cancer Institute as part of routine diagnostics in January 2021. The success of implementing WGS has relied on adhering to a comprehensive protocol including recording patient information, sample collection, shipment and storage logistics, sequencing data interpretation and reporting, integration into clinical decision-making and data usage. This protocol describes the use of fresh-frozen samples that are necessary for WGS but can be challenging to implement in pathology laboratories accustomed to using formalin-fixed paraffin-embedded samples. In addition, the protocol outlines key considerations to guide uptake of WGS in routine clinical care in hospitals worldwide.

Spatial transcriptomics and the anatomical pathologist: Molecular meets morphology.

In recent years anatomical pathology has been revolutionised by the incorporation of molecular findings into routine diagnostic practice, and in some diseases the presence of specific molecular alterations are nowessential for diagnosis. Spatial transcriptomics describes a group of technologies that provide up to transcriptome-wide expression profiling while preserving the spatial origin of the data, with many of these technologies able to provide these data using a single tissue section. Spatial transcriptomics allows expression profiling of highly specific areas within a tissue section potentially to subcellular resolution, and allows correlation of expression data with morphology, tissue type and location relative to other structures. While largely still research laboratory-based, several spatial transcriptomics methods have now achieved compatibility with formalin-fixed paraffin-embedded tissue (FFPE), allowing their use in diagnostic tissue samples, and with further development potentially leading to their incorporation in routine anatomical pathology practice. This mini review provides an overview of spatial transcriptomics methods, with an emphasis on platforms compatible with FFPE tissue, approaches to assess the data and potential applications in anatomical pathology practice.

Prognostic role of tumor budding in oral squamous cell carcinoma: a retrospective study

Background: Tumor budding (TB) is defined as a single cell or a cluster of up to five tumor cells at the invasion front of all oral squamous cell carcinoma (OSCC) cases. Tumor budding is considered a marker of many important events in oral carcinoma, including the epithelial-mesenchymal transition, invasion, metastasis, and for further prognosis. Methods: A total of 30 clinically and histopathologically diagnosed cases of OSCC were retrieved from the archival of the Department of Oral Pathology and Microbiology. After assessing the sections for the presence of TB, it is further categorized into high-intensity TB and low-intensity TB. Results: We found a strong association between lymph node metastasis, lymph node metastasis, and histopathological grading in the current study. There was no association between TB and a patient's survival rate. Conclusions: This study emphasizes the significance of tumor budding, its relevance to prognosis, and reproducibility, as well as the significance of its evaluation and incorporation into routine surgical pathology practice in the management of OSCC. As a result, we believe that tumor budding is a crucial factor in determining tumor behavior.

Anaplastic large cell lymphomas with equivocal DUSP22 FISH results: recommendations for clinical reporting and diagnostic evaluation

Anaplastic large cell lymphoma (ALCL), one of the most common T-cell lymphomas, shows unifying pathological features but is clinically and genetically heterogeneous. One genetic subgroup, characterized by recurrent DUSP22 rearrangements (R), has distinct morphologic, immunophenotypic, and molecular features and can be identified in routine pathology practice using a breakapart (BAP) fluorescence in situ hybridization (FISH) probe. However, some cases show equivocal BAP-FISH findings (BAP-FISHEQ) and the features of these cases are poorly understood. Here, we sought to characterize DUSP22 BAP-FISHEQ ALCLs further. First, we applied an immunohistochemistry (IHC) algorithm using TIA1, pSTAT3Y705, and LEF1, which can predict DUSP22-R with high accuracy. Among 37 BAP-FISHEQ ALCLs, 18 (49%) were IHC-algorithm positive (IHCPOS), 8 (21%) were IHC-algorithm negative (IHCNEG), and 11 (30%) were IHCEQ. In 32 BAP-FISHEQ cases, we also applied a dual-color, dual-fusion (D-FISH) probe for t(6;7)(p25.3;q32.3), which accounts for 45% of DUSP22-R ALCLs. Among BAP-FISHEQ cases, D-FISH was positive in 10/18 IHCPOS cases (56%), 0/9 IHCEQ cases (0%), and 0/5 IHCNEG cases (0%). Median survival in BAP-FISHEQ ALCLs was 105 months, intermediate between BAP-FISHPOS ALCLs (median survival not reached) and BAP-FISHNEG ALCLs (19 months). Thus, DUSP22 BAP-FISHEQ ALCLs are clinicopathologically heterogeneous, likely due to an admixture of cases with an unbalanced DUSP22-R and cases with focal deletions without rearrangement. For clinical reporting, we recommend that DUSP22 BAP-FISHEQ ALCLs be reported as equivocal, and not be grouped with BAP-FISHPOS ALCLs. Clinical adoption of an IHC algorithm, possibly supplemented by t(6; 7) D-FISH, could facilitate genetic subtyping in about two-thirds of BAP-FISHEQ ALCLs.

Needle in a haystack or elephant in the room? Identifying germline predisposition syndromes in the setting of a new myeloid malignancy diagnosis.

Myeloid malignancies associated with germline predisposition syndromes account for up to 10% of myeloid neoplasms. They are classified into three categories by the proposed 5th Edition of the World Health Organization Classification of Hematolymphoid Tumors: (1) neoplasms with germline predisposition without a pre-existing platelet disorder or organ dysfunction, (2) neoplasms with germline predisposition and pre-existing platelet disorder, or (3) neoplasms with germline predisposition and potential organ dysfunction. Recognizing these entities is critical because patients and affected family members benefit from interfacing with hematologists who specialize in these disorders and can facilitate tailored treatment strategies. However, identification of these syndromes in routine pathology practice is often challenging, as characteristic findings associated with these diagnoses at baseline are frequently absent, nonspecific, or impossible to evaluate in the setting of a myeloid malignancy. Here we review the formally classified germline predisposition syndromes associated with myeloid malignancies and summarize practical recommendations for pathologists evaluating a new myeloid malignancy diagnosis. Our intent is to empower clinicians to better screen for germline disorders in this common clinical setting. Recognizing when to suspect a germline predisposition syndrome, pursue additional ancillary testing, and ultimately recommend referral to a cancer predisposition clinic or hematology specialist, will ensure optimal patient care and expedite research to improve outcomes for these individuals.

394 Gene expression based molecular test proves clinical validity as diagnostic aid for the differential diagnosis of psoriasis and eczema in formalin fixed and paraffin embedded tissue

Abstract Highly specific and efficient drugs have been developed to treat noncommunicable chronic inflammatory skin diseases (ncISD). Due to their specificity, these drugs require precise diagnostics to attribute the most efficient treatment to each patient. Diagnosis is complicated by the complex pathogenesis of ncISD and their clinical and histological overlap. Especially, precise diagnosis of psoriasis and atopic eczema is difficult in special cases, and molecular tools need to be developed to support gold standard diagnosis. Psoriasis and eczema are among the most prevalent skin diseases worldwide with a combined incidence rate of at least 2%. Although more than a dozen of immune-modulating therapies, particularly monoclonal antibodies targeting specific cytokines or their receptors, have become available over the last decade allowing highly effective treatment, the ultimate breakthrough would include accurate diagnostic tools. Diagnosis of both diseases largely depends on a subjective visual exam and histopathological examination. Due to phenotypical overlaps of both diseases, up to 50% of cases with a palmoplantar localization are misdiagnosed. To close this diagnostic gap, a gene expression-based classifier using NOS2 and CCL27 has been proposed and its clinical validity examined and proven in various patient cohorts. This study aims to develop a real-time based molecular classifier (MC) to distinguish psoriasis from atopic eczema in formalin-fixed, paraffin-embedded (FFPE)-fixed skin samples for diagnostic measures and to evaluate the potential of minimally invasive microbiopsies and noninvasive tape strips or sampling disks for molecular diagnosis. The FFPE, micro-(Ø1mm) and macrobiopsies (Ø4–6 mm), and tape strips were collected from psoriasis and eczema lesions and analysed by real-time polymerase chain reaction (PCR) for the expression of NOS2 and CCL27. A molecular classifier (MC) was established using a linear regression model. We transferred the RNAprotect-based molecular classifier to FFPE samples and were able to produce comparable results. Whereas the RNAprotect based MC distinguished psoriasis from eczema with a sensitivity and specificity for psoriasis of 97.7% and 100%, respectively, and an AUC of 0.99, the FFPE-based classifier determined probabilities for psoriasis with a sensitivity and specificity and of 92% and 100%, respectively, and an AUC of 0.97. To test if microbiopsies are also adequate tissue samples for the MC, we analysed gene expression in 83 pairs of macro- and microbiopsies by real-time quantitative-PCR. Delta-CT values showed no significant difference between macro- and microbiopsies. The MC led to reliable results in the vast majority of samples (91.57%) independent of biopsy size, with a small increase of misclassification (4.98%). The FFPE-based molecular classifier (MC) precisely separates eczema from psoriasis and efficiently identifies subtypes of both diseases. The reliability of the two markers NOS2 and CCL27 has been shown in FFPE tissue facilitating a possible implementation of this molecular diagnostic aid in routine clinical pathological practice. We further show that the gene expression profile of RNA later fixed microbiopsies is comparable to standard 4–6 mm biopsies and that microbiopsies are equally suited for the MC. We demonstrate the potential of tape strips of inflamed epidermis for molecular diagnostics of ncISD. Due to the minimally invasive sampling procedure, tape stripping may be particularly useful for the testing of visible and sensitive skin areas and in children as well as for repetitive sampling procedures necessary to monitor treatment responses over time. In summary, the MC discriminates psoriasis from eczema producing meaningful results in a broad range of skin tissue derived from invasive to minimally invasive sampling techniques. Further efforts are required to simplify and shorten the labor- and cost-intensive procedures of RNA isolation and real-time PCR. One possible solution is a fully automated and closed system, which would allow the integration of molecular diagnostics into the routine patient management at the point of care.

A Curious Case of Omental Oxalate Crystals in a Patient With Struma Ovarii: Pointers to an Unusual Clinicopathological Scenario.

Percutaneous image-guided biopsies are becoming increasingly common in routine pathology practice, with the greater omentum emerging as a common target. We present herein an account of a middle-aged lady with a complex ovarian mass, omental thickening, and raised serum CA125; clinically suspected to have advanced ovarian malignancy. Fine needle aspiration cytology (FNAC) from the ovarian mass was inconclusive. Omental biopsy revealed only refractile, birefringent crystalline material with surrounding foreign body giant cell reaction; thus surprising the clinical team. Subsequent resection of the ovarian mass showed a teratoma composed exclusively of thyroid tissue, diagnosed as struma ovarii. The omental crystals, interpreted as calcium oxalate crystals, were possibly a consequence of colloid seeding during the ovarian mass FNAC.

Independent Validation of the International Grading System for Medullary Thyroid Carcinoma: A Single Institution Experience

Medullary thyroid carcinoma (MTC), an uncommon C cell thyroid malignancy, accounts for a disproportionate number of thyroid cancer deaths. To predict MTC clinical behavior, the recent international MTC grading system (IMTCGS) was published combining features from the Memorial Sloan Kettering Cancer Center and Royal North Shore Hospital grading systems that incorporates mitotic count, necrosis, and Ki67 proliferative index (Ki67PI). The IMTCGS appears promising, but independent validation data are limited. Here, we applied the IMTCGS to our institutional MTC cohort and assessed its ability to predict clinical outcomes. Our cohort comprised 87 MTCs (30 germline and 57 sporadic). Slides for each case were reviewed by 2 pathologists and histologic features recorded. Ki67 immunostaining was performed on all cases. Each MTC was graded with the IMTCGS based on tumor necrosis, Ki67PI, and mitotic count. Cox regression analysis was performed to assess the impact of various clinical and pathological data on disease outcomes, including overall survival (OS), disease-free survival, disease-specific survival (DSS), and distant metastasis-free survival. In our MTC cohort, 18.4% (n = 16/87) were IMTCGS high grade. IMTCGS grade was strongly prognostic for OS, disease-free survival, DSS, and distant metastasis-free survival on univariate analysis and multivariable analysis in both the entire MTC cohort and in the sporadic subset. Among the individual IMTCGS parameters, while all 3 were associated with poorer survival outcomes on univariate analysis, necrosis had the strongest association with all survival parameters on multivariable analysis, whereas Ki67PI or mitotic count was associated only with OS and DSS. This retrospective study independently demonstrates that the IMTCGS is valid for grading MTCs. Our findings support incorporating IMTCGS into routine pathology practice. IMTCGS grading may help clinicians to better predict the prognosis of MTC. Future studies may shed light on how MTC grading should impact treatment protocols.

The prognostic significance of non-lymphoid immune cells of the tumor microenvironment, including neutrophils, eosinophils, and mast cells in breast carcinomas

Background and objectiveThe prognostic importance of lymphoid cells in the tumor microenvironment and their effect on treatment response have been demonstrated in many cancer types. However, there are limited studies on non-lymphoid immune cells. Conflicting results have been obtained regarding the effects of these cells on prognosis. Materials and methodsA total of 331 patients who underwent surgery for breast cancer were included. Patients that received neoadjuvant chemotherapy and those with distant metastasis were excluded. CD 15 immunohistochemistry was performed to detect tumor-infiltrating neutrophils (TINs) and eosinophils (TIEs), while Toluidine Blue histochemistry was performed to detect tumor-infiltrating mast cells (TIMs). ResultsHigh TINs were statistically associated with low ER expression (p < 0.001), low PR expression (p = 0.001), high Ki-67 proliferation index (p = 0.008), and HER2/TN molecular subtypes (p = 0.001). High TIEs were associated with low ER expression (p = 0.001), high Ki67 proliferation index (p = 0.005), and HER2/TN molecular subtype (p = 0.002). High TIMs were associated with high PR expression (p = 0.024), low Ki-67 proliferation index (p = 0.003), and high survival rate (p = 0.006). TIMs and TIEs were good prognostic factors for overall survival in Luminal A and Luminal B subtypes, while TINs and TIEs were found to be independent risk factors for disease-free survival. ConclusionThe evaluation of components of the tumor microenvironment including TINs, TIEs, and TIMs is easy and practical. High TIMs and TIEs are independent prognostic factors, especially in luminal molecular subtype of invasive breast carcinoma. However, to use this parameter in routine pathology practice, more studies from different centers and standard evaluation are needed.

Abstract P6-04-07: Primary Diagnosis of Breast Biopsies supported by AI versus Microscope: Multi-Site Clinical Reader Study

Abstract Objective This study aimed to clinically validate the use of an AI-based solution by pathologists for the primary diagnosis of breast core needle biopsies as compared with the gold standard practice (review on the microscope). Methods A two-arm prospective reader study comparing the performance of pathologists using an AI-based solution with pathologists using a microscope was performed at two sites (different staining and digital scanners). Both arms were compared to ground truth (GT) established by the consensus of two breast pathologists. Rates of major discrepancies between each arm and GT, as determined by an adjudicating pathologist, were compared. Results Eight pathologists participated in the study and reported on 385 cases (442 HES and 330 H&amp;E slides), each case being reported twice, once in each study arm. Pathologists first reviewed only H&amp;E/HES slides, if requested and available, they were provided with IHCs, while the AI results were on H&amp;E/HES only. The major discrepancy rates of the microscope arm and of the AI arm against GT were 4.42% and 3.12%, respectively, demonstrating a 29.4% reduction in major discrepancies. Pathologists with AI demonstrated very high accuracy for the detection of invasive carcinoma with sensitivity and specificity of 100% for both, as well as for DCIS/ADH with sensitivity of 92.4% and specificity of 97.8%. Conclusions This multi-site reader study reports diagnostic accuracy improvements by pathologists performing diagnosis and reporting with the support of a first read AI solution for breast biopsies. The AI solution performed accurately and generalized well for different staining platforms and different scanners. Thus, AI solutions could be used as significant aiding tools for pathologists in clinical decision-making in routine pathology practice, enhancing the quality and reproducibility of diagnosis. Citation Format: Anne Salomon, Alona Nudelman, Joanna Cyrta, Marina Maklakovski, Anat Albrecht Shach, Geraldine Sebag, Giuseppe Mallel, Ira Krasnitsky, Tali Feinberg, Manuela Vecsler, Judith Sandbank. Primary Diagnosis of Breast Biopsies supported by AI versus Microscope: Multi-Site Clinical Reader Study [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-04-07.

Multicenter automatic detection of invasive carcinoma on breast whole slide images.

Breast cancer is one of the most prevalent cancers worldwide and pathologists are closely involved in establishing a diagnosis. Tools to assist in making a diagnosis are required to manage the increasing workload. In this context, artificial intelligence (AI) and deep-learning based tools may be used in daily pathology practice. However, it is challenging to develop fast and reliable algorithms that can be trusted by practitioners, whatever the medical center. We describe a patch-based algorithm that incorporates a convolutional neural network to detect and locate invasive carcinoma on breast whole-slide images. The network was trained on a dataset extracted from a reference acquisition center. We then performed a calibration step based on transfer learning to maintain the performance when translating on a new target acquisition center by using a limited amount of additional training data. Performance was evaluated using classical binary measures (accuracy, recall, precision) for both centers (referred to as "test reference dataset" and "test target dataset") and at two levels: patch and slide level. At patch level, accuracy, recall, and precision of the model on the reference and target test sets were 92.1% and 96.3%, 95% and 87.8%, and 73.9% and 70.6%, respectively. At slide level, accuracy, recall, and precision were 97.6% and 92.0%, 90.9% and 100%, and 100% and 70.8% for test sets 1 and 2, respectively. The high performance of the algorithm at both centers shows that the calibration process is efficient. This is performed using limited training data from the new target acquisition center and requires that the model is trained beforehand on a large database from a reference center. This methodology allows the implementation of AI diagnostic tools to help in routine pathology practice.

A new practical method of estimating tumoral microenvironment parameters of possible prognostic significance in patients with invasive breast carcinoma: Combined microenvironment score

Background and objectiveIn recent years, the tumor microenvironment has become increasingly recognized as an influential factor in breast cancer development and growth. The parameters that form the microenvironment are the tumor stroma ratio and tumor infiltrating lymphocytes. In addition, tumor budding, which shows the ability of the tumor to metastasize, gives information about the progression of the tumor. In this study, the combined microenvironment score (CMS) was determined with these parameters, and the relationship between CMS and prognostic parameters and survival was evaluated. Materials and methodsIn our study, tumor stroma ratio, tumor infiltrating lymphocytes, and tumor budding were evaluated in hematoxylin-eosin sections of 419 patients with invasive ductal carcinoma. Patients were scored separately for each of these parameters, and these scores were summed to determine the CMS. The patients were divided into 3 groups according to CMS and the relationship between CMS and prognostic parameters and the survival of the patients was studied. ResultsThe patients with CMS 3 had higher histological grade and Ki67 proliferation index compared to CMS 1 and 2. Additionally, lymphovascular invasion, axillary lymph node and distant metastasis were more common. Disease-free, and overall survival were significantly shortened in the CMS 3 group. CMS was found as an independent risk factor for DFS (HR: 2.144 (95 % CI: 1.219–3.77) p: 0.008), but not an independent risk factor for OS. ConclusionCMS is a prognostic parameter that can be easily evaluated and does not require extra time and cost. Evaluating the morphological parameters of the microenvironment with a single scoring system will contribute to routine pathology practice and predict patient prognosis.

Improving sarcoma classification by using RNA hybridisation capture sequencing in sarcomas of uncertain histogenesis of young individuals

Our aim was to utilise a 241-gene RNA hybridisation capture sequencing (CaptureSeq) gene panel to identify unexpected fusions in undifferentiated, unclassified or partly classified sarcomas of young individuals (<40 years). The purpose was to determine the utility and yield of a large, targeted fusion panel as a tool for classifying tumours that do not fit typical diagnostic entities at the time of the original diagnosis. RNA hybridisation capture sequencing was performed on 21 archival resection specimens. Successful sequencing was obtained in 12 of 21 samples (57%), two of which (16.6%) harboured translocations. A novel NEAT1::GLI1 fusion, not previously reported in the literature, presented in a young patient with a tumour in the retroperitoneum, which displayed low grade epithelioid cells. The second case, a localised lung metastasis in a young male, demonstrated a EWSR1::NFATC2 translocation. No targeted fusions were identified in the remaining 83.4% (n=10) of cases. Forty-three per cent of the samples failed sequencing as a result of RNA degradation. RNA-based sequencing is an important tool, which helps to redefine the classification of unclassified or partly classified sarcomas of young adults by identifying pathogenic gene fusions in up to 16.6% of the cases. Unfortunately, 43% of the samples underwent significant RNA degradation, falling below the sequencing threshold. As CaptureSeq is not yet available in routine pathology practice, increasing awareness of the yield, failure rate and possible aetiological factors for RNA degradation is fundamental to maximise laboratory procedures to improve RNA integrity, allowing the potential identification of significant gene alterations in solid tumours.