{"title":"SMARCA4-deficient Sinonasal Malignant Tumor With Striated Muscle and Neuroendocrine Differentiation: A Case Report and Letter to the Editor.","authors":"Mingfang Sun, Jian Wang, Qingfu Zhang, Xuyong Lin","doi":"10.1097/PAS.0000000000002114","DOIUrl":"10.1097/PAS.0000000000002114","url":null,"abstract":"","PeriodicalId":7772,"journal":{"name":"American Journal of Surgical Pathology","volume":" ","pages":"497-499"},"PeriodicalIF":5.6,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10037265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mohammadreza Pakyari, Navin R Mahadevan, Eleanor Russell-Goldman
{"title":"Concurrent PTEN and PDGFRB Alterations Characterize Storiform Collagenoma.","authors":"Mohammadreza Pakyari, Navin R Mahadevan, Eleanor Russell-Goldman","doi":"10.1097/PAS.0000000000002146","DOIUrl":"10.1097/PAS.0000000000002146","url":null,"abstract":"<p><p>Storiform collagenoma is a rare mesenchymal skin tumor that is composed of thickened collagen bundles arranged in a characteristic storiform pattern with a relatively hypocellular CD34-positive spindle cell component. Storiform collagenoma is most often sporadic, but multiple lesions can occur in Cowden syndrome, which is characterized by germline alterations in PTEN (phosphatase and tensin homolog) on chromosome 10. Here, we investigated the molecular pathogenesis of storiform collagenoma using a targeted next-generation DNA sequencing platform, including 5 sporadic cases and one case associated with Cowden syndrome. Recurrent PTEN alterations were identified in all cases, with biallelic PTEN inactivation observed in the case associated with Cowden syndrome and one sporadic case. Unexpectedly, we also identified recurrent activating mutations in the platelet-derived growth factor receptor beta ( PDGFRB ) gene. This included a missense substitution in the D5 Ig-like domain of PDGFRB in the Cowden syndrome-associated case. In addition, we report missense alterations in the juxtamembrane domain of PDGFRB in 4 of 5 (80%) sporadic cases, including mutations that have been previously described in sporadic myofibroma and myopericytoma. Therefore, we confirm the neoplastic nature of storiform collagenoma, we expand the spectrum of reported PDGFRB alterations in mesenchymal tumors and we suggest a possible collaborative role for PTEN and PDGFRB in the pathogenesis of storiform collagenoma.</p>","PeriodicalId":7772,"journal":{"name":"American Journal of Surgical Pathology","volume":" ","pages":"150-156"},"PeriodicalIF":5.6,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71410264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"SPARC Is a Novel Positive Immunohistochemical Marker of Epithelioid Mesothelioma to Differentiate It From Lung Adenocarcinoma and/or Squamous Cell Carcinoma.","authors":"Tetsuya Nakagiri, Vishwa J Amatya, Kei Kushitani, Takahiro Kambara, Kohei Aoe, Ihiro Endo, Yoshihiro Miyata, Morihito Okada, Yukio Takeshima","doi":"10.1097/PAS.0000000000002147","DOIUrl":"10.1097/PAS.0000000000002147","url":null,"abstract":"<p><p>Epithelioid mesothelioma with a solid histologic pattern (solid epithelioid mesothelioma) is difficult to distinguish from a poorly differentiated squamous cell lung carcinoma and/or solid lung adenocarcinoma. Thus, immunohistochemical markers are essential for diagnosis; however, the sensitivity and specificity of pre-existing mesothelial markers are suboptimal, particularly for differentiation from squamous cell carcinoma. Using a cancer-dependency map, we analyzed gene expression data of pleural mesothelioma and non-small cell lung cancer cell lines (squamous cell carcinoma and adenocarcinoma) and identified secreted protein acidic and cysteine-rich (SPARC) as a promising candidate for the differential diagnosis of epithelioid mesothelioma from lung squamous cell carcinoma and/or lung adenocarcinoma. SPARC expression in mesothelioma and lung cancer cell lines was validated using reverse-transcription polymerase chain reaction, western blotting, and immunohistochemistry. Immunohistochemical staining was performed using anti-SPARC antibodies against solid epithelioid mesothelioma, solid lung adenocarcinoma, and poorly differentiated lung squamous cell carcinoma. SPARC positivity was seen in 42/45 (93.3%) of solid epithelioid mesothelioma, 2/40 (5%) solid lung adenocarcinoma, and 2/45 (4.5%) of lung squamous cell carcinomas. The sensitivity, specificity, and diagnostic accuracy for differentiating solid epithelioid mesothelioma from lung cancer (solid lung adenocarcinoma and poorly differentiated lung squamous cell carcinoma) were 93.3, 95.2, and 94.6%, respectively. In conclusion, SPARC is a novel mesothelial marker that can be used to differentiate epithelioid mesothelioma from squamous cell carcinoma and lung adenocarcinoma.</p>","PeriodicalId":7772,"journal":{"name":"American Journal of Surgical Pathology","volume":" ","pages":"140-149"},"PeriodicalIF":5.6,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71410178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bo Yang, William Chour, Cristo Guardado Salazar, Paul Zamiara, Ryan J Schmidt, Gordana Raca, Nick Shillingford, Shengmei Zhou, Mikako Warren, David M Parham, Bruce Pawel, Larry L Wang
{"title":"Pediatric Sertoli-Leydig Cell Tumors of the Ovary: An Integrated Study of Clinicopathological Features, Pan-cancer-Targeted Next-generation Sequencing and Chromosomal Microarray Analysis From a Single Institution.","authors":"Bo Yang, William Chour, Cristo Guardado Salazar, Paul Zamiara, Ryan J Schmidt, Gordana Raca, Nick Shillingford, Shengmei Zhou, Mikako Warren, David M Parham, Bruce Pawel, Larry L Wang","doi":"10.1097/PAS.0000000000002149","DOIUrl":"10.1097/PAS.0000000000002149","url":null,"abstract":"<p><p>Sertoli-Leydig cell tumors (SLCTs) are currently classified into 3 molecular subtypes: DICER1 -mutant (younger patient age), FOXL2 -mutant, and DICER1/FOXL2 -wildtype. However, it is not clear whether all pediatric SLCTs are DICER1 -mutant molecular subtypes and whether other molecular genetic aberrations besides DICER1 are involved in the pathogenesis and prognosis of these tumors. We studied comprehensive data for 8 cases of pediatric SLCTs, including clinicopathological features, pan-cancer-targeted next-generation sequencing/OncoKids panel, and chromosomal microarray analysis, to further analyze the correlation among clinicopathological features, molecular genetic aberrations, and prognosis. The ages of the patients ranged from 4 to 16 years (median, 14 y). Seven cases were moderately differentiated, and one was poorly differentiated with heterologous mesenchymal elements. Two cases had heterologous epithelium or retiform elements. Follow-up was available for all 8 patients (median, 49.5 mo). Seven patients were alive without evidence of recurrence or metastasis, and only case 5 developed metastases (synchronous bilateral pulmonary tumors with rhabdomyosarcomatous differentiation). All 8 tumors were found to harbor somatic hotspot DICER1 mutations, and 5 patients carried germline DICER1 mutations (2 of them had the phenotype of DICER1 syndrome). Together with recent studies, the DICER1 mutation frequency is 100% in pediatric SLCTs (n=27, age≤16 y). Copy number alterations were detected in 3 tumors; the only recurrent copy number alterations was the gain of whole chromosome 6 in case 5 and case 8. This is the first report describing clinicopathological features and molecular alterations in pediatric SLCTs. Our results demonstrate that all pediatric SLCTs belong to the DICER1 -mutant molecular subtype, highlighting that somatic hotspot DICER1 mutation detection has high sensitivity (100%) for the auxiliary diagnosis of pediatric SLCTs (age ≤16 y). Some pediatric SLCTs harbor molecular genetic aberrations other than DICER1 mutation, and their significance needs further study.</p>","PeriodicalId":7772,"journal":{"name":"American Journal of Surgical Pathology","volume":" ","pages":"194-203"},"PeriodicalIF":4.5,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72013163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jerzy Lasota, Małgorzata Chłopek, Maciej Kaczorowski, Klubíčková Natálie, Janusz Ryś, Janusz Kopczyński, Oksana Sulaieva, Michael Michal, Anna Kruczak, Agnieszka Harazin-Lechowska, Magdalena Szczepaniak, Olena Koshyk, Agnieszka Hałoń, Piotr Czapiewski, Zied Abdullaev, Artur Kowalik, Kenneth D Aldape, Michal Michal, Markku Miettinen
{"title":"Utility of Immunohistochemistry With Antibodies to SS18-SSX Chimeric Proteins and C-Terminus of SSX Protein for Synovial Sarcoma Differential Diagnosis.","authors":"Jerzy Lasota, Małgorzata Chłopek, Maciej Kaczorowski, Klubíčková Natálie, Janusz Ryś, Janusz Kopczyński, Oksana Sulaieva, Michael Michal, Anna Kruczak, Agnieszka Harazin-Lechowska, Magdalena Szczepaniak, Olena Koshyk, Agnieszka Hałoń, Piotr Czapiewski, Zied Abdullaev, Artur Kowalik, Kenneth D Aldape, Michal Michal, Markku Miettinen","doi":"10.1097/PAS.0000000000002144","DOIUrl":"10.1097/PAS.0000000000002144","url":null,"abstract":"<p><p>Synovial sarcoma is a relatively common soft tissue tumor characterized by highly specific t(X;18)(p11;q11) translocation resulting in the fusion of SS18 with members of SSX gene family. Typically, detection of SS18 locus rearrangement by fluorescence in situ hybridization or SS18 :: SSX fusion transcripts confirms the diagnosis. More recently, immunohistochemistry (IHC) for SS18-SSX chimeric protein (E9X9V) and C-terminus of SSX (E5A2C) showed high specificity and sensitivity for synovial sarcoma. This study screened a cohort of >1000 soft tissue and melanocytic tumors using IHC and E9X9V and E5A2C antibodies. Three percent (6/212) of synovial sarcomas were either negative for SS18-SSX or had scattered positive tumor cells (n=1). In these cases, targeted RNA next-generation sequencing detected variants of SS18 :: SSX chimeric transcripts. DNA methylation profiles of 2 such tumors matched with synovial sarcoma. A few nonsynovial sarcoma tumors (n=6) revealed either focal SS18-SSX positivity (n=1) or scattered positive tumor cells. However, targeted RNA next-generation sequencing failed to detect SS18 :: SSX transcripts in these cases. The nature of this immunopositivity remains elusive and may require single cell sequencing studies. All synovial sarcomas showed positive SSX IHC. However, a mosaic staining pattern or focal loss of expression was noticed in a few cases. Strong and diffuse SSX immunoreactivity was also seen in epithelioid sclerosing osteosarcoma harboring EWSR1 :: SSX1 fusion, while several sarcomas and melanocytic tumors including cellular blue nevus (5/7, 71%) revealed focal to diffuse, mostly weak to intermediate SSX staining. The SS18-SSX and SSX IHC is a useful tool for synovial sarcoma differential diagnosis, but unusual immunophenotype should trigger molecular genetic testing.</p>","PeriodicalId":7772,"journal":{"name":"American Journal of Surgical Pathology","volume":" ","pages":"97-105"},"PeriodicalIF":5.6,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71410179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Michelle R Downes, Arndt Hartmann, Steven Shen, Toyonori Tsuzuki, Bas W G van Rhijn, Lukas Bubendorf, Theodorus H van der Kwast, Liang Cheng
{"title":"International Society of Urological Pathology (ISUP) Consensus Conference on Current Issues in Bladder Cancer. Working Group 1: Comparison of Bladder Cancer Grading System Performance.","authors":"Michelle R Downes, Arndt Hartmann, Steven Shen, Toyonori Tsuzuki, Bas W G van Rhijn, Lukas Bubendorf, Theodorus H van der Kwast, Liang Cheng","doi":"10.1097/PAS.0000000000002059","DOIUrl":"10.1097/PAS.0000000000002059","url":null,"abstract":"<p><p>Grade is a key prognostic factor in determining progression in nonmuscle invasive papillary urothelial carcinomas. The 2 most common grading methods in use worldwide are the World Health Organization (WHO) 2004 and 1973 schemes. The International Society of Urological Pathology (ISUP) organized the 2022 consensus conference in Basel, Switzerland on current issues in bladder cancer and tasked working group 1 to make recommendations for future iterations of bladder cancer grading. For this purpose, the ISUP developed in collaboration with the European Association of Urology a 10-question survey for their memberships to understand the current use of grading schemes by pathologists and urologists and to ascertain the areas of potential improvements. An additional survey was circulated to the ISUP membership for their opinion on interobserver variability in grading, reporting of urine cytology, and challenges encountered in grade assignment. Comprehensive literature reviews were performed on bladder cancer grading prognosis and interobserver variability along with The Paris System for urine cytology. There are notable differences in practice patterns between North American and European pathologists in terms of used grading scheme and diagnosis of papillary urothelial neoplasm of low malignant potential. Areas of common ground include difficulty in grade assignment, a desire to improve grading criteria, and a move towards subclassifying high-grade urothelial carcinomas. The surveys and in-person voting demonstrated a strong preference to refine current grading into a 3-tier scheme with the division of WHO 2004 high grade into clinically relevant categories. More variable opinions were voiced regarding the use of papillary urothelial carcinoma with low malignant potential.</p>","PeriodicalId":7772,"journal":{"name":"American Journal of Surgical Pathology","volume":" ","pages":"e1-e10"},"PeriodicalIF":5.6,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9538355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kevin Mijares, Rocco Ferrandino, Raymond Chai, Scott Roof, Swati Bhardwaj, Marshall Posner, William H Westra
{"title":"Circulating Tumor HPV DNA in Patients With Head and Neck Carcinoma: Correlation With HPV Genotyping.","authors":"Kevin Mijares, Rocco Ferrandino, Raymond Chai, Scott Roof, Swati Bhardwaj, Marshall Posner, William H Westra","doi":"10.1097/PAS.0000000000002134","DOIUrl":"10.1097/PAS.0000000000002134","url":null,"abstract":"<p><p>Circulating tumor human papillomavirus DNA (ctHPVDNA) testing using digital-droplet polymerase chain reaction (PCR) detects fragments of tumor-modified human papillomavirus (HPV) in the plasma of patients with HPV-associated head and neck squamous cell carcinomas (HNSCCs). Its impact on tumor surveillance and primary diagnosis is limited by unresolved issues relating to sensitivity and specificity. The study population consisted of patients with HNSCC who had undergone ctHPVDNA testing. HPV status was determined by p16 immunohistochemistry and PCR-HPV genotyping on the tumor samples. For discrepant cases (HPV-positive/ctHPVDNA-negative), HPV status was confirmed by RNA in situ hybridization and, when possible, targeted single-nucleotide polymorphisms genotyping. A total of 167 patients had ctHPVDNA testing, and 141 tumors were HPV positive by p16 immunohistochemistry and PCR genotyping. Genotypes included types 16 (91.5%), 33 (4.3%), 35 (2.1%), and 18 (2.1%). ctHPVDNA was detected in 133 (94.3%) of HPV-positive HNSCCs but in none of the HPV-negative HNSCCs. Four of the 5 p16-positive cases that were negative by PCR and ctHPVDNA were positive by RNA in situ hybridization, and in 2 of these cases, rare high-risk genotypes were identified. ctHPVDNA had a sensitivity of 91.7%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 63.6%. The likelihood that patients with HPV-positive HNSCC have detectable ctHPVDNA is high. Non-HPV16 genotypes contribute to discrepancies but only in a small subset of cases. This finding validates ongoing efforts to use ctHPVDNA as a surveillance tool, and even as a primary diagnostic assay in patients presenting with masses in the neck and/or oropharynx.</p>","PeriodicalId":7772,"journal":{"name":"American Journal of Surgical Pathology","volume":" ","pages":"80-87"},"PeriodicalIF":5.6,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41094398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
David L Kolin, Marisa R Nucci, Gulisa Turashvili, Sharon J Song, Sophie Corbett-Burns, Matthew Cesari, Martin C Chang, Blaise Clarke, Elizabeth Demicco, Valerie Dube, Cheng-Han Lee, Marjan Rouzbahman, Patricia Shaw, Paola Dal Cin, David Swanson, Brendan C Dickson
{"title":"Targeted RNA Sequencing Highlights a Diverse Genomic and Morphologic Landscape in Low-grade Endometrial Stromal Sarcoma, Including Novel Fusion Genes.","authors":"David L Kolin, Marisa R Nucci, Gulisa Turashvili, Sharon J Song, Sophie Corbett-Burns, Matthew Cesari, Martin C Chang, Blaise Clarke, Elizabeth Demicco, Valerie Dube, Cheng-Han Lee, Marjan Rouzbahman, Patricia Shaw, Paola Dal Cin, David Swanson, Brendan C Dickson","doi":"10.1097/PAS.0000000000002142","DOIUrl":"10.1097/PAS.0000000000002142","url":null,"abstract":"<p><p>Low-grade endometrial stromal sarcoma (LGESS) represents a morphologically and genetically heterogenous mesenchymal neoplasm. Previous work has shown that approximately half of LGESS are characterized by JAZF1::SUZ12 gene fusions, while a smaller proportion involves rearrangement of other genes. However, a subset of cases has no known genetic abnormalities. To better characterize the genomic landscape of LGESS, we interrogated a cohort with targeted RNA sequencing (RNA-Seq). Cases previously diagnosed as low-grade endometrial stromal neoplasia (n=51) were identified and re-reviewed for morphology and subjected to RNA-Seq, of which 47 were successfully sequenced. The median patient age was 49 years (range: 19 to 85). The most commonly detected fusions were JAZF1::SUZ12 (n=26, 55%) and BRD8::PHF1 (n=3, 6%). In addition to the usual/typical LGESS morphology, some JAZF1::SUZ12 fusion tumors showed other morphologies, including fibrous, smooth muscle, sex-cord differentiation, and myxoid change. Novel translocations were identified in 2 cases: MEAF6::PTGR2 and HCFC1::PHF1 . Ten tumors (21%) had no identifiable fusion, despite a similar morphology and immunophenotype to fusion-positive cases. This suggests that a subset of cases may be attributable to fusion products among genes that are not covered by the assay, or perhaps altogether different molecular mechanisms. In all, these findings confirm that RNA-Seq is a potentially useful ancillary test in the diagnosis of endometrial stromal neoplasms and highlight their diverse morphology.</p>","PeriodicalId":7772,"journal":{"name":"American Journal of Surgical Pathology","volume":" ","pages":"36-45"},"PeriodicalIF":5.6,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49688419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Markku Miettinen, Zied Abdullaev, Rust Turakulov, Martha Quezado, Alejandro Luiña Contreras, Christian A Curcio, Janusz Rys, Malgorzata Chlopek, Jerzy Lasota, Kenneth D Aldape
{"title":"Assessment of The Utility of The Sarcoma DNA Methylation Classifier In Surgical Pathology.","authors":"Markku Miettinen, Zied Abdullaev, Rust Turakulov, Martha Quezado, Alejandro Luiña Contreras, Christian A Curcio, Janusz Rys, Malgorzata Chlopek, Jerzy Lasota, Kenneth D Aldape","doi":"10.1097/PAS.0000000000002138","DOIUrl":"10.1097/PAS.0000000000002138","url":null,"abstract":"<p><p>Diagnostic classification of soft tissue tumors is based on histology, immunohistochemistry, genetic findings, and radiologic and clinical correlations. Recently, a sarcoma DNA methylation classifier was developed, covering 62 soft tissue and bone tumor entities. The classifier is based on large-scale analysis of methylation sites across the genome. It includes DNA copy number analysis and determines O 6 methylguanine DNA methyl-transferase methylation status. In this study, we evaluated 619 well-studied soft tissue and bone tumors with the sarcoma classifier. Problem cases and typical examples of different entities were included. The classifier had high sensitivity and specificity for fusion sarcomas: Ewing, synovial, CIC -rearranged, and BCOR -rearranged. It also performed well for leiomyosarcoma, malignant peripheral nerve sheath tumors (MPNST), and malignant vascular tumors. There was low sensitivity for diagnoses of desmoid fibromatosis, neurofibroma, and schwannoma. Low specificity of matches was observed for angiomatoid fibrous histiocytoma, inflammatory myofibroblastic tumor, Langerhans histiocytosis, schwannoma, undifferentiated sarcoma, and well-differentiated/dedifferentiated liposarcoma. Diagnosis of lipomatous tumors was greatly assisted by the detection of MDM2 amplification and RB1 loss in the copy plot. The classifier helped to establish diagnoses for KIT-negative gastrointestinal stromal tumors, MPNSTs with unusual immunophenotypes, and undifferentiated melanomas. O 6 methylguanine DNA methyl-transferase methylation was infrequent and most common in melanomas (35%), MPNSTs (11%), and undifferentiated sarcomas (11%). The Sarcoma Methylation Classifier will likely evolve with the addition of new entities and refinement of the present methylation classes. The classifier may also help to define new entities and give new insight into the interrelationships of sarcomas.</p>","PeriodicalId":7772,"journal":{"name":"American Journal of Surgical Pathology","volume":" ","pages":"112-122"},"PeriodicalIF":5.6,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10842611/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71419872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}