{"title":"TABLE OF CONTENTS (p/u from previous issue w/updates)","authors":"","doi":"10.1053/S0740-2570(25)00090-5","DOIUrl":"10.1053/S0740-2570(25)00090-5","url":null,"abstract":"","PeriodicalId":49548,"journal":{"name":"Seminars in Diagnostic Pathology","volume":"42 5","pages":"Article 150954"},"PeriodicalIF":3.5,"publicationDate":"2025-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144896457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Differential diagnosis of multiple myeloma.","authors":"Miguel Dario Cantu, Weina Chen","doi":"10.1016/j.semdp.2025.150944","DOIUrl":"https://doi.org/10.1016/j.semdp.2025.150944","url":null,"abstract":"<p><p>Distinguishing multiple myeloma from B-cell lymphomas can be a diagnostic challenge. There can be significant morphologic, immunophenotypic and clinical overlap that may require additional molecular genetic ancillary studies and careful clinical review to render an accurate diagnosis. The focus of this review will be on the differential diagnosis of multiple myeloma with an emphasis on low-grade B-cell lymphomas with plasmacytic differentiation and aggressive B-cell lymphomas with plasmablastic morphology that can mimic true plasma cell neoplasms. Diagnostic approaches to plasmablastic neoplasms, including extramedullary plasmablastic plasmacytoma and distinguishing features of B-cell lymphomas with plasmablastic morphology are discussed. Low-grade B-cell lymphomas with plasmacytic differentiation, including lymphoplasmacytic lymphoma, marginal zone lymphoma, chronic lymphocytic leukemia/small lymphocytic lymphoma, and other low-grade B-cell lymphomas that less frequently exhibit plasmacytic differentiation such as follicular lymphoma and mantle cell lymphoma are also included. Multiple myeloma with CCND1:IGH, which can mimic low-grade B-cell lymphomas and post-treatment plasmacytic proliferations following treatment for B-cell lymphomas with plasmacytic differentiation are also discussed.</p>","PeriodicalId":49548,"journal":{"name":"Seminars in Diagnostic Pathology","volume":" ","pages":"150944"},"PeriodicalIF":3.5,"publicationDate":"2025-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144856894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Extrahepatic cholangiocarcinoma: Current concepts in histopathology, immunohistochemistry, and molecular diagnostics.","authors":"Jared Beyersdorf, M Lisa Zhang","doi":"10.1016/j.semdp.2025.150949","DOIUrl":"https://doi.org/10.1016/j.semdp.2025.150949","url":null,"abstract":"<p><p>Cholangiocarcinoma (CCA) makes up a diverse group of malignancies that originate from the biliary epithelium. Despite its rarity, this is a highly aggressive group of diseases with a high mortality, which has been increasing on a global scale. Classification of CCA is based on the anatomical site of origin and consists of intrahepatic (iCCA), perihilar (pCCA), and distal (dCCA) cholangiocarcinoma. The pathologic diagnosis of CCA can be challenging from multiple standpoints, including tissue acquisition and interpretation. Surgery is the only curative treatment, but patients often present at late stages, which may not be amenable to surgical treatment. Novel therapies are emerging for CCA, and early genetic testing is essential to identify candidate patients. There is a need for further developments in immunohistochemistry and molecular characterization of CCA to enable earlier diagnosis, especially from limited samples. This review provides a concise overview of current concepts in the pathology of CCA, focusing on diagnostic challenges, histology, staging, immunohistochemistry, and evolving molecular features.</p>","PeriodicalId":49548,"journal":{"name":"Seminars in Diagnostic Pathology","volume":" ","pages":"150949"},"PeriodicalIF":3.5,"publicationDate":"2025-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144859851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The expanding family of ALK-rearranged Mesenchymal Neoplasms","authors":"Abbas Agaimy","doi":"10.1016/j.semdp.2025.150947","DOIUrl":"10.1016/j.semdp.2025.150947","url":null,"abstract":"<div><div>The increasing use of next generation sequencing (NGS) technologies has resulted in a rapid increase in molecularly defined mesenchymal entities and enabled molecular characterization of existing phenotypically defined entities. These recent developments have expanded the clinicopathological spectrum of <em>ALK</em>-rearranged neoplasia, at same time highlighting a wide array of non-<em>ALK</em> fusions in many ALK immunoreactive neoplasms. This led to emergence of an “<em>ALK</em> vs. <em>non-ALK fusion</em>” concept among ALK immunoreactive neoplasms. The <em>ALK</em> fusion category includes morphologically defined entities (inflammatory myofibroblastic tumor and related neoplasms and epithelioid fibrous histiocytoma) as well as emerging fibro-/myxoid (“fibroblastic”) neoplasms of skin/ superficial soft tissue and vocal cords and ALK+ (mostly pediatric) histiocytoses. Lastly, diverse categories of unclassified <em>ALK</em> fusion neoplasms have been reported that display tyrosine kinase-like phenotype (CD34+/ S100+), foamy cell/ pseudolipogenic features and unclassified high-grade morphology. On the other hand, the “non-<em>ALK</em> fusion” category expands to include entities with regular/ frequent ALK reactivity (angiomatoid fibrous histiocytoma with <em>EWSR1/FUS::CREB</em>, spindle/ epithelioid cell rhabdomyosarcoma with <em>EWSR1/FUS::TFCP2</em> and unclassified sarcomas with <em>EWSR1/FUS::CREB</em> fusions). The latter category has challenged the value of IHC and/ or FISH alone to confirm or rule out <em>ALK</em> alterations, underlining the pivotal role of NGS to verify the exact driver fusion. Under circumstances, identification of the exact fusion may have therapeutic and/ or prognostic implications. This overview discusses the main <em>ALK</em> fusion entities with emphasis on differential diagnosis.</div></div>","PeriodicalId":49548,"journal":{"name":"Seminars in Diagnostic Pathology","volume":"42 5","pages":"Article 150947"},"PeriodicalIF":3.5,"publicationDate":"2025-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144849476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"NCOA1/2/3-rearranged low-grade fibroblastic/myofibroblastic spindle cell tumors: including emerging entities beyond the WHO 5th edition of Bone and Soft Tissue Tumors - a systematic review.","authors":"Rayan Sibira, Josephine K Dermawan","doi":"10.1016/j.semdp.2025.150945","DOIUrl":"https://doi.org/10.1016/j.semdp.2025.150945","url":null,"abstract":"","PeriodicalId":49548,"journal":{"name":"Seminars in Diagnostic Pathology","volume":" ","pages":"150945"},"PeriodicalIF":3.5,"publicationDate":"2025-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144856895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Histopathological and genetic landscape of pancreatic ductal adenocarcinoma and its variants","authors":"Nicholas J. Caldwell, M. Lisa Zhang","doi":"10.1016/j.semdp.2025.150948","DOIUrl":"10.1016/j.semdp.2025.150948","url":null,"abstract":"<div><div>Pancreatic ductal adenocarcinoma (PDAC) remains a deadly disease where proper pathologic evaluation ensures appropriate clinical management. This review article summarizes literature regarding problematic, uncommon, and new challenges in PDAC evaluation and highlights recent molecular advancements. Microscopically, the morphologies of PDAC are diverse, and certain features, such as foamy gland morphology, large duct pattern of invasion, cancerization of ducts, and neoadjuvant therapy effects, are important to recognize and distinguish from mimickers. Immunohistochemistry can be useful in select settings for distinguishing malignant from benign pancreatic epithelium. Morphologic subtypes of PDAC have their own distinct clinical, histologic, and molecular features that provide insight into disease mechanisms and therapy. Finally, therapies targeting molecular alterations can significantly impact some patients, and molecular subtyping of PDAC has rapidly advanced in the last decade through detailed transcriptomic evaluation.</div></div>","PeriodicalId":49548,"journal":{"name":"Seminars in Diagnostic Pathology","volume":"42 5","pages":"Article 150948"},"PeriodicalIF":3.5,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144895694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Pancreatic neuroendocrine neoplasms: current paradigms and diagnostic challenges.","authors":"Grace J Kwon, Chanjuan Shi","doi":"10.1016/j.semdp.2025.150946","DOIUrl":"https://doi.org/10.1016/j.semdp.2025.150946","url":null,"abstract":"<p><p>Pancreatic neuroendocrine neoplasms (PanNENs) are broadly divided into well-differentiated pancreatic neuroendocrine tumors (PanNETs) and poorly differentiated pancreatic neuroendocrine carcinomas (PanNECs). Grading is based on the mitotic count and Ki-67 proliferation index. PanNETs demonstrate typical neuroendocrine morphology, including nested and trabecular growth patterns, and \"salt-and-pepper\" coarse, clumped chromatin, whereas PanNECs can look like any poorly differentiated carcinoma. Differentiation of PanNETs from PanNECs and other hypercellular pancreatic neoplasms may sometimes be challenging but is crucial for patient management. Immunohistochemistry will demonstrate positivity for neuroendocrine markers. The advent of sequencing technology has elucidated critical signaling pathways potentially involved in the development of PanNENs, while also highlighting potential predispositions due to previously known and newly identified germline mutations.</p>","PeriodicalId":49548,"journal":{"name":"Seminars in Diagnostic Pathology","volume":" ","pages":"150946"},"PeriodicalIF":3.5,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144849475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}