Archives of pathology & laboratory medicine最新文献

{"title":"Bridging the Clinical-Computational Transparency Gap in Digital Pathology.","authors":"Qiangqiang Gu, Ankush Patel, Matthew G Hanna, Jochen K Lennerz, Chris Garcia, Mark Zarella, David McClintock, Steven N Hart","doi":"10.5858/arpa.2023-0250-RA","DOIUrl":"10.5858/arpa.2023-0250-RA","url":null,"abstract":"<p><strong>Context.—: </strong>Computational pathology combines clinical pathology with computational analysis, aiming to enhance diagnostic capabilities and improve clinical productivity. However, communication barriers between pathologists and developers often hinder the full realization of this potential.</p><p><strong>Objective.—: </strong>To propose a standardized framework that improves mutual understanding of clinical objectives and computational methodologies. The goal is to enhance the development and application of computer-aided diagnostic (CAD) tools.</p><p><strong>Design.—: </strong>This article suggests pivotal roles for pathologists and computer scientists in the CAD development process. It calls for increased understanding of computational terminologies, processes, and limitations among pathologists. Similarly, it argues that computer scientists should better comprehend the true use cases of the developed algorithms to avoid clinically meaningless metrics.</p><p><strong>Results.—: </strong>CAD tools improve pathology practice significantly. Some tools have even received US Food and Drug Administration approval. However, improved understanding of machine learning models among pathologists is essential to prevent misuse and misinterpretation. There is also a need for a more accurate representation of the algorithms' performance compared to that of pathologists.</p><p><strong>Conclusions.—: </strong>A comprehensive understanding of computational and clinical paradigms is crucial for overcoming the translational gap in computational pathology. This mutual comprehension will improve patient care through more accurate and efficient disease diagnosis.</p>","PeriodicalId":93883,"journal":{"name":"Archives of pathology & laboratory medicine","volume":" ","pages":"276-287"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141319253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diagnostic Pearls and Pitfalls in the Evaluation of Small Biopsies From the Bile Duct and Ampulla.","authors":"Alyssa M Krasinskas","doi":"10.5858/arpa.2024-0160-RA","DOIUrl":"10.5858/arpa.2024-0160-RA","url":null,"abstract":"<p><strong>Context.—: </strong>Histopathologic evaluation of bile duct and ampullary biopsies can be challenging. Biopsies from these sites are often tiny, scant, and/or fragmented. When assessing these biopsies, there is significant overlap between reactive atypia and malignancy, in situ precursor lesions can be misinterpreted as malignancy, and nonprimary tumors can mimic primary disease.</p><p><strong>Objective.—: </strong>To provide diagnostic pearls and pitfalls in the evaluation of small biopsies from the biliary tract.</p><p><strong>Data sources.—: </strong>Literature review of published studies and the author's own observations.</p><p><strong>Conclusions.—: </strong>Because the procedures for obtaining specimens from the bile duct and ampulla are invasive, pathologists need to try to make definitive diagnoses. Diagnostic clues/pearls, ancillary studies, and recognition of various pitfalls can assist in providing accurate and confident diagnoses.</p>","PeriodicalId":93883,"journal":{"name":"Archives of pathology & laboratory medicine","volume":" ","pages":"e47-e53"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142741643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Conventional Cytogenetic Analysis of Constitutional Abnormalities: A 20-Year Review of Proficiency Test Results From the College of American Pathologists/American College of Medical Genetics and Genomics Cytogenetics Committee.","authors":"Brittney Boles, Juli-Anne Gardner, Catherine W Rehder, Brynn Levy, Gopalrao V Velagaleti, Reha M Toydemir, William R Sukov, Daniel P Larson, Yang Cao, Christopher Mixon, Rachel K Vanderscheldon, Ying S Zou, Caroline Astbury, Karen D Tsuchiya, Jess F Peterson","doi":"10.5858/arpa.2024-0048-CP","DOIUrl":"10.5858/arpa.2024-0048-CP","url":null,"abstract":"<p><strong>Context.—: </strong>The joint College of American Pathologists/American College of Medical Genetics and Genomics Cytogenetics Committee works to ensure competency and proficiency of clinical cytogenetics testing laboratories through proficiency testing programs for various clinical tests offered by such laboratories, including the evaluation of constitutional abnormalities.</p><p><strong>Objective.—: </strong>To review and analyze 20 years of constitutional chromosome analysis proficiency testing results (2003-2022), primarily utilizing G-banded karyograms.</p><p><strong>Design.—: </strong>A retrospective review of results from 2003 through 2022 was performed, identifying challenges addressing constitutional disorders. The chromosomal abnormalities and overall performance were evaluated.</p><p><strong>Results.—: </strong>A total of 184 cases from 161 proficiency testing challenges were administered from 2003 through 2022. Challenges consisted of metaphase images and accompanying clinical history for evaluation of numerical and/or structural abnormalities. Of the 184 cases, only 2 (1%) failed to reach an 80% grading consensus for recognition of the abnormality. Both cases illustrated the limitations of correctly characterizing some chromosomal abnormalities, including recombinant chromosomal abnormalities and isochromosome identification. In addition, 2 cases failed to reach a consensus for nomenclature reporting: 1 with an isochromosome and another with a duplication.</p><p><strong>Conclusions.—: </strong>This 20-year review illustrates the high rate of competency and proficiency of cytogenetic laboratories in the correct identification of constitutional chromosome abnormalities.</p>","PeriodicalId":93883,"journal":{"name":"Archives of pathology & laboratory medicine","volume":" ","pages":"211-216"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141262327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diagnostic Pearls and Pitfalls in the Evaluation of Biopsies of the Pancreas.","authors":"Claudio Luchini","doi":"10.5858/arpa.2023-0426-RA","DOIUrl":"10.5858/arpa.2023-0426-RA","url":null,"abstract":"<p><strong>Context.—: </strong>The examination of small pancreatic biopsies is a difficult task for pathologists. This is due to the scant and fragmented material often obtained from diagnostic procedures as well as the significant overlap between different neoplastic and nonneoplastic entities. In the upcoming neoadjuvant era, biopsies could become even more important, representing the only possibility to look at the real histomorphology of tumors before chemotherapy-induced modifications.</p><p><strong>Objectives.—: </strong>To summarize and discuss the state-of-the-art diagnostic workflow for small pancreatic biopsies, including the most important morphologic and immunohistochemical features and molecular alterations. The main diagnostic pearls and pitfalls of this challenging scenario are also discussed. The most important topics of this review are represented by: (1) pancreatic ductal adenocarcinoma, along with its main differential diagnoses, including autoimmune pancreatitis; (2) solid hypercellular neoplasms, including neuroendocrine neoplasms, acinar cell carcinoma, pancreatoblastoma, and solid pseudopapillary neoplasms; and (3) cystic lesions. Real-world considerations will also be presented and discussed.</p><p><strong>Data sources.—: </strong>Sources included a literature review of published studies and the author's own work.</p><p><strong>Conclusions.—: </strong>The correct diagnosis of pancreatic lesions is a crucial step in the therapeutic journey of patients. It should be based on robust, standardized, and reliable hallmarks. As presented and discussed here, the integration of morphology with immunohistochemistry, and, in selected cases, with molecular analysis, represents a decisive step in this complex scenario.</p>","PeriodicalId":93883,"journal":{"name":"Archives of pathology & laboratory medicine","volume":" ","pages":"e54-e62"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139934638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measurable Residual Disease Analysis by Flow Cytometry and Correlation With Molecular Measurable Residual Disease in Acute Promyelocytic Leukemia: A Real-World Prospective Study.","authors":"Zhihao Wen, Xinran Xue, Shuhua Li, Yu Liu, Yongmei Jin, Nenggang Jiang, Hongyan Liao","doi":"10.5858/arpa.2023-0460-OA","DOIUrl":"10.5858/arpa.2023-0460-OA","url":null,"abstract":"<p><strong>Context.—: </strong>Acute promyelocytic leukemia (APL) is a subtype of acute myeloid leukemia distinguished by its rapidly progressive and fatal clinical course. Measurable/minimal residual disease (MRD) monitoring is vital for the prognosis and clinical management of acute myeloid leukemia.</p><p><strong>Objective.—: </strong>To examine the immunophenotypes of the residual leukemic cells, evaluate the performance of multiparametric flow cytometry (FCM) measuring MRD, and compare it with molecular monitoring in patients diagnosed with APL.</p><p><strong>Design.—: </strong>Two hundred seventy-seven patients with APL were enrolled. Immunophenotypes were prospectively analyzed by a 1-tube-10-color antibody panel via FCM. MRD of APL with PML::RARα was detected by real-time quantitative polymerase chain reaction (RQ-PCR). The clinical value of MRD as an indicator of survival was also examined.</p><p><strong>Results.—: </strong>APL showed 5 distinct patterns of residual leukemic cells, based on CD45 and side-scatter scattergram, all with CD9 positivity and a previously unrealized loss of CD117. FCM-based MRD evaluation showed a concordance rate of 87.7% with PCR. At the end of the consolidation therapy, MRD measured by both PCR and FCM could differentiate patients with longer and shorter overall survival (OS) (P = .04 and P = .03, respectively). Patients with APL variant had a shorter OS than patients with APL who harbored PML::RARα (P < .001).</p><p><strong>Conclusions.—: </strong>CD9 is a reliable marker to differentiate residual leukemic cells from normally differentiating myeloid cells. FCM demonstrated a high comparability to PCR-MRD and an excellent performance in predicting OS, and thus could potentially be used as a routine indicator in the clinical management of patients with APL.</p>","PeriodicalId":93883,"journal":{"name":"Archives of pathology & laboratory medicine","volume":" ","pages":"262-270"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141262513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Notable Histologic Findings in a \"Normal\" Cohort: The National Institutes of Health Genotype-Tissue Expression (GTEx) Project.","authors":"Philip A Branton, Leslie Sobin, Mary Barcus, Kelly B Engel, Sarah R Greytak, Ping Guan, Jim Vaught, Helen M Moore","doi":"10.5858/arpa.2023-0468-OA","DOIUrl":"10.5858/arpa.2023-0468-OA","url":null,"abstract":"<p><strong>Context.—: </strong>The National Institutes of Health (NIH) Genotype-Tissue Expression (GTEx) project was designed to evaluate how genetic variation and epigenetic effects influence gene expression in normal tissue.</p><p><strong>Objective.—: </strong>To ensure that the grossly normal-appearing tissues collected were free from disease, each specimen underwent histologic evaluation.</p><p><strong>Design.—: </strong>In total, nearly 30 000 tissue aliquots collected from almost 1000 postmortem donors underwent histologic review by project pathologists, and detailed observations of any abnormalities or lesions present were recorded.</p><p><strong>Results.—: </strong>Despite sampling of normal-appearing tissue, in-depth review revealed incidental findings among GTEx samples that included neoplastic, autoimmune, and genetic conditions; the incidence of some of these conditions among GTEx donors differed from those previously reported for other populations. A number of age-related abnormalities observed during histologic review of tissue specimens are also described.</p><p><strong>Conclusions.—: </strong>Histologic findings from the GTEx project may serve to improve populational awareness of several conditions and present a unique opportunity for others to explore age- and sex-influenced conditions. Resources from the study, including histologic image and sequencing data, are publicly available for research.</p>","PeriodicalId":93883,"journal":{"name":"Archives of pathology & laboratory medicine","volume":" ","pages":"233-241"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140856815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Clinical Performance of the Line Immunoassay and Digital Liquid Chip Method for Detecting Autoimmune Liver Disease Autoantibodies.","authors":"Heye Lv, Ao Deng, Yijun Chen, Zhenzhen Su","doi":"10.5858/arpa.2024-0057-OA","DOIUrl":"10.5858/arpa.2024-0057-OA","url":null,"abstract":"<p><strong>Context.—: </strong>The identification of autoantibodies associated with autoimmune liver disease (ALD) is crucial for diagnosis and management. Various laboratory methods have been introduced to detect autoantibody profiles. However, the variable performance of these assays may create challenges for clinicians and patients.</p><p><strong>Objective.—: </strong>To investigate the concordance rates and diagnostic performance of 2 commercially available assays, line immunoassay (LIA) and digital liquid chip method (DLCM), in patients with ALD.</p><p><strong>Design.—: </strong>A total of 291 serum samples were collected, consisting of 180 sera from patients with ALD and 111 sera from controls. The samples were detected through LIA and DLCM. The agreement and diagnostic performance of each assay were analyzed.</p><p><strong>Results.—: </strong>There was substantial to almost perfect agreement among prevalent autoantibodies (anti-mitochondrial antibody M2; antibodies against gp210, Sp100, and Ro52). Nevertheless, the Cohen κ coefficient of some uncommon autoantibodies (anti-LKM-1, anti-LC-1, and anti-SLA/LP) between the 2 methods was not ideal. LIA showed slightly better sensitivity, accuracy, and negative predictive value, while DLCM exhibited slightly higher specificity and positive predictive value.</p><p><strong>Conclusions.—: </strong>LIA and DLCM demonstrated comparable performance for the detection of common ALD-related autoantibodies. LIA seemed to be more sensitive, while DLCM displayed more specificity. However, standardization of ALD autoantibody detection still faces challenges between these diverse detection systems. Comprehensive interlaboratory validation is essential to mitigate potential misunderstanding and confusion among patients and clinicians.</p>","PeriodicalId":93883,"journal":{"name":"Archives of pathology & laboratory medicine","volume":" ","pages":"271-275"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141236430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Histologic and Quality Assessment of Genotype-Tissue Expression (GTEx) Research Samples: A Large Postmortem Tissue Collection.","authors":"Leslie Sobin, Mary Barcus, Philip A Branton, Kelly B Engel, Judy Keen, David Tabor, Kristin G Ardlie, Sarah R Greytak, Nancy Roche, Brian Luke, Jim Vaught, Ping Guan, Helen M Moore","doi":"10.5858/arpa.2023-0467-OA","DOIUrl":"10.5858/arpa.2023-0467-OA","url":null,"abstract":"<p><strong>Context.—: </strong>The National Institutes of Health Genotype-Tissue Expression (GTEx) project was developed to elucidate how genetic variation influences gene expression in multiple normal tissues procured from postmortem donors.</p><p><strong>Objective.—: </strong>To provide critical insight into a biospecimen's suitability for subsequent analysis, each biospecimen underwent quality assessment measures that included evaluation for underlying disease and potential effects introduced by preanalytic factors.</p><p><strong>Design.—: </strong>Electronic images of each tissue collected from nearly 1000 postmortem donors were evaluated by board-certified pathologists for the extent of autolysis, tissue purity, and the type and abundance of any extraneous tissue. Tissue-specific differences in the severity of autolysis and RNA integrity were evaluated, as were potential relationships between these markers and the duration of postmortem interval and rapidity of death.</p><p><strong>Results.—: </strong>Tissue-specific challenges in the procurement and preservation of the nearly 30 000 tissue specimens collected during the GTEx project are summarized. Differences in the degree of autolysis and RNA integrity number were observed among the 40 tissue types evaluated, and tissue-specific susceptibilities to the duration of postmortem interval and rapidity of death were observed.</p><p><strong>Conclusions.—: </strong>Ninety-five percent of tissues were of sufficient quality to support RNA sequencing analysis. Biospecimens, annotated whole slide images, de-identified clinical data, and genomic data generated for GTEx represent a high-quality and comprehensive resource for the scientific community that has contributed to its use in approximately 1695 articles. Biospecimens and data collected under the GTEx project are available via the GTEx portal and authorized access to the Database of Genotypes and Phenotypes; procedures and whole slide images are available from the National Cancer Institute.</p>","PeriodicalId":93883,"journal":{"name":"Archives of pathology & laboratory medicine","volume":" ","pages":"217-232"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141155945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of Molecular Testing Methodologies for CIC-Rearranged Sarcomas.","authors":"Selene C Koo, Maria Cardenas, Patricia Stow, Jennifer Neary, David A Wheeler, Zonggao Shi, Larissa V Furtado","doi":"10.5858/arpa.2024-0407-OA","DOIUrl":"https://doi.org/10.5858/arpa.2024-0407-OA","url":null,"abstract":"<p><strong>Context.—: </strong>Molecular detection of a capicua transcriptional repressor (CIC) rearrangement is critical for diagnosing CIC-rearranged sarcoma (CIC-RS) but is analytically challenging.</p><p><strong>Objective.—: </strong>To compare the technical performance of fluorescence in situ hybridization (FISH), whole-transcriptome sequencing (RNA-seq), and DNA methylation profiling for CIC-rearrangement detection in a large, mainly pediatric cohort.</p><p><strong>Design.—: </strong>The study cohort consisted of 44 distinct patient tumors that were positive, equivocal, or suggestive for CIC rearrangement, including 18 central nervous system and 26 extra-central nervous system solid tumors. Forty tumors underwent FISH to detect CIC rearrangement, 31 underwent transcriptome sequencing, and 34 underwent methylation array analysis. Results for tumors tested by multiple testing modalities were compared.</p><p><strong>Results.—: </strong>Fusions were detected in 27 cases: CIC::double homeobox 4 (DUX4) (n = 15), CIC::NUT midline carcinoma family member 1 (NUTM1) (n = 4), CIC::leucine twenty homeobox (LEUTX) (n = 3), CIC::NUT family member 2B (NUTM2B) (n = 1), ataxin 1 (ATXN1)::NUTM1 (n = 1), ATXN1::NUT family member 2A/B (NUTM2A/B) (n = 1), CIC::DUX4 proximity effect (n = 1), and dedicator of cytokinesis 1 (DOCK1)::DUX4 (n = 1). Twenty-five tumors were tested by all 3 testing modalities. Apparent false-negative rates were 20% (3 of 15) for CIC FISH, 14% (2 of 14) for transcriptome sequencing, and 14% (2 of 14) for methylation array analysis. Both false-negative methylation array results had CIC::LEUTX fusion.</p><p><strong>Conclusions.—: </strong>Awareness of molecular testing pitfalls in the appropriate detection of CIC rearrangement is critical. Any CIC FISH result may need to be further confirmed, either with unequivocal immunohistochemical support or by another molecular method. A positive RNA-seq or methylation array analysis result may be sufficient evidence for a diagnosis of CIC-RS in the appropriate histologic context. A negative or inconclusive/unclassified RNA-seq or methylation array analysis result in a tumor with high initial suspicion for CIC-RS likely requires careful reevaluation.</p>","PeriodicalId":93883,"journal":{"name":"Archives of pathology & laboratory medicine","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143476896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Loss of H3K27me3 Is Not Specific to Malignant Triton Tumor: Immunohistochemical Analysis of 23 Cases of Embryonal Rhabdomyosarcoma.","authors":"Laura M Warmke, Jessica L Davis, Alyaa Al-Ibraheemi, Michael Arnold, Serena Tan, Archana Shenoy, Lea F Surrey, David M Parham, Erin R Rudzinski","doi":"10.5858/arpa.2024-0199-OA","DOIUrl":"https://doi.org/10.5858/arpa.2024-0199-OA","url":null,"abstract":"<p><strong>Context.—: </strong>Malignant peripheral nerve sheath tumor (MPNST) is a rare, often high-grade sarcoma. A small subset of MPNST shows evidence of heterologous rhabdomyoblastic differentiation, also known as malignant triton tumor (MTT). Immunohistochemical loss of histone 3 lysine 27 trimethylation (H3K27me3) has previously been described as a reliable marker for both MPNST and MTT.</p><p><strong>Objective.—: </strong>To assess the loss of H3K27me3 as a potential tool for discriminating MTT from embryonal rhabdomyosarcoma (ERMS).</p><p><strong>Design.—: </strong>We studied the immunohistochemical expression of H3K27me3 in 23 pediatric cases of confirmed ERMS. Of the 23 patients, 21 were male and 2 were female, with an age range of 2 months to 18 years (median, 5 years). Most of the tumors arose in the paratesticular soft tissue (n = 14), with other locations including the pelvis (n = 3), thigh (n = 2), abdomen (n = 1), orbit (n = 1), prostate gland (n = 1), and parotid gland (n = 1). All cases had characteristic morphologic features of ERMS.</p><p><strong>Results.—: </strong>By immunohistochemistry, all tested cases expressed desmin (18 of 18), myogenin (20 of 20), and MyoD1 (5 of 5). More than half of the cases (12 of 23; 52%) showed loss (nuclear absence) of H3K27me3, defined as staining in less than 5% of the tumor cells. The remaining cases demonstrated some degree of partial staining with H3K27me3, ranging from 5 to 40% of the tumor cells. No significant correlation between H3K27me3 expression and clinicopathologic features was identified.</p><p><strong>Conclusions.—: </strong>Loss of H3K27me3 frequently occurs in ERMS (52%) and is not reliable in distinguishing ERMS from MTT.</p>","PeriodicalId":93883,"journal":{"name":"Archives of pathology & laboratory medicine","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143434583","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}