Acta Cytologica最新文献

{"title":"Primary Melanoma of the Lung: A Vanishing Entity.","authors":"Tanner Storozuk, Melissa Tjota, Prince Ntiamoah, Pankhuri Wanjari, Anna Biernacka, Ward Reeves, Tatjana Antic","doi":"10.1159/000546441","DOIUrl":"10.1159/000546441","url":null,"abstract":"<p><strong>Introduction: </strong>Primary melanoma of the lung has been considered an extremely rare and highly aggressive malignancy that accounts for 0.01% of all primary lung tumors. Molecular studies, as well as pertinent clinical history, have since brought into question whether these tumors truly represent primary lesions of the lung. The current study evaluates a series of four melanomas of the lung to assess whether primary melanoma of the lung is truly a diagnostic consideration, or if these cases represent metastases of other primary sites.</p><p><strong>Methods: </strong>The pathology archives at the University of Chicago Medical Center were searched for patients who underwent robotic or endobronchial ultrasound-guided fine needle aspiration from 2018 to 2024. Clinicopathologic data, including demographics, fine needle aspiration results, and follow-up information including molecular studies and surgical resections, were collected from patients' electronic medical record.</p><p><strong>Results: </strong>In total 15,959 robotic-guided/endobronchial ultrasound-guided FNAs were reviewed, with 2 cases (0.0001%) being metastatic melanoma with no known cutaneous primary after immunohistochemical and molecular studies. Both patients had molecular studies performed. Notable mutations included BRAF, TERT, NRAS, CDKN2A, and NF1, which are frequently seen in cutaneous melanomas. High tumor mutational burden (UV signature with >98 mutations per megabase) was also detected by next-generation sequencing.</p><p><strong>Conclusion: </strong>Based upon molecular signatures, clinical history, and presumed lack of precursor cell type within the bronchial epithelium, melanomas arising within the lung are most likely metastatic tumors.</p>","PeriodicalId":6959,"journal":{"name":"Acta Cytologica","volume":" ","pages":"1-6"},"PeriodicalIF":1.6,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144075337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PD-L1 in Lung Cytology: The Path for Standardization.","authors":"Mohammed S I Mansour, Gennaro Acanfora, Giancarlo Troncone, Hans Brunnström, Elena Vigliar","doi":"10.1159/000546275","DOIUrl":"10.1159/000546275","url":null,"abstract":"<p><strong>Background: </strong>The advent of programmed cell death-1/programmed death-ligand 1 (PD-1/PD-L1) inhibitors has revolutionized lung cancer treatment, necessitating accurate PD-L1 immunohistochemical (IHC) assessment. While standardized for formalin-fixed paraffin-embedded histological samples, PD-L1 testing on cytology remains challenging. This review aims to address the complexities of PD-L1 IHC in cytology, focusing on validation guidelines, quality assessment, cytohistological correlation, and interobserver variability.</p><p><strong>Summary: </strong>This review synthesizes current guidelines and research on PD-L1 IHC in cytology; in particular, recent College of American Pathologists (CAP) guidelines emphasize the necessity for rigorous validation, particularly for non-formalin-fixed specimens. As far as cytohistological concordance studies are concerned, the review of 48 original articles revealed significant variability in PD-L1 expression, with concordance rates ranging from 54 to 100% at the 1% cutoff and 82-100% at the 50% cutoff. Finally, interobserver variability, particularly in the 1-49% PD-L1 expression range, further complicates accurate assessment. The review also discusses the challenges associated with quality assessment in cytology, including the lack of standardized control materials and external quality assessment (EQA) programs specifically tailored for cytological samples.</p><p><strong>Key messages: </strong>PD-L1 testing in cytology is feasible but faces substantial challenges compared to histological specimens. Validation of PD-L1 IHC protocols for cytological preparations, especially non-formalin-fixed samples, is essential. Concordance between cytological and histological PD-L1 expression is variable, highlighting the need for caution in interpretation. Interobserver variability, particularly in cases with intermediate PD-L1 expression (1-49%), affects diagnostic reproducibility. The development of standardized quality control materials and EQA programs for cytology is urgently needed to support consistent and reliable PD-L1 testing.</p>","PeriodicalId":6959,"journal":{"name":"Acta Cytologica","volume":" ","pages":"1-16"},"PeriodicalIF":1.6,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144075335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of Estrogen Receptor, Progesterone Receptor, and Human Epidermal Growth Factor Receptor 2 on Cell Blocks and Core Needle Biopsies in Metastatic Breast Cancer: A Real-World Experience.","authors":"Chen Lossos, Sandra Sanchez, Hiro Nonogaki, Edward Gabrielson, Ashley Cimino-Mathews, Zahra Maleki","doi":"10.1159/000546274","DOIUrl":"10.1159/000546274","url":null,"abstract":"<p><strong>Introduction: </strong>The status of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) plays a crucial role in the management of patients with metastatic breast cancer. Herein we report our experience on ER, PR, and HER2 immunostains on cell block and core needle biopsy (CNB) specimens of metastatic breast cancers.</p><p><strong>Methods: </strong>Cytological samples of metastatic breast cancer with associated cell blocks or core needle biopsies were identified, on which ER, PR, or HER2 were ordered from 2019 to 2021. Both fine needle aspiration specimens and body effusion fluids were included. Patients' demographics, cancer histological subtype, biopsy site, specimen type (cell block or CNB) for immunohistochemistry and ER, PR, and HER2 expression were recorded.</p><p><strong>Results: </strong>192 specimens from 177 patients were identified. Patients' mean age was 58.5 years (range 24-96). The majority of samples were obtained from patients with invasive ductal carcinoma. Staining was performed on core biopsies (n = 74/192, 38.5%) and on cell blocks (n = 118/192, 61.5%). Pleural fluid (n = 75) was the most commonly sampled site, followed by the liver (n = 48) and lymph nodes (n = 44). ER, PR, and HER2 were positive in 76.3%, 79.3%, and 13.2% of samples, respectively. Concordantly, ER+PR+HER2- was the most common sample phenotype. Seven samples had insufficient tissue to evaluate ER, PR, or HER2 status.</p><p><strong>Conclusion: </strong>ER, PR, and HER2 immunohistochemical staining can be performed on cell block or CNB specimens of metastatic breast cancer and can provide reliable information to clinicians for optimal patient care.</p>","PeriodicalId":6959,"journal":{"name":"Acta Cytologica","volume":" ","pages":"1-10"},"PeriodicalIF":1.6,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143958849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Risk of Malignancy Ranges and Category Percentage Assignment in Cytopathology Reporting Systems: Are They Useful Quality Assurance Indicators?","authors":"Lester J Layfield, Zubair W Baloch","doi":"10.1159/000546228","DOIUrl":"10.1159/000546228","url":null,"abstract":"<p><strong>Background: </strong>Quality assurance (QA) is essential in cytopathology to ensure diagnostic accuracy. Common QA methods include peer reviews, 10% random reviews, and benchmarking against published standards. Benchmarking, which compares institutional data on specimen category assignment and risk of malignancy (ROM) with published body site reviews, helps evaluate performance and identify areas of improvement. Cytopathology reporting systems for various body sites categorize specimens based on ROM estimates. The diagnostic categories and ROM estimates in non-gynecologic cytopathology systems can serve as quality metrics to improve practices and maintain high standards of patient care.</p><p><strong>Summary: </strong>A well-developed QA system in cytology is crucial for ensuring diagnostic accuracy and minimizing errors. By using tools like secondary reviews, retrospective analyses, and structured reporting systems, laboratories can improve practices, detect errors, and maintain high standards of patient care.</p><p><strong>Key messages: </strong>The cytopathology reporting systems help provide categorical information that can guide clinicians, ensuring quality assurance (QA) and accuracy in diagnosis across various organ sites. Institutional data on category assignments and ROM can be compared with broader literature to assess accuracy and QA. Significant outliers in ROM for specific categories should trigger peer review and potential retraining to improve diagnostic accuracy.</p>","PeriodicalId":6959,"journal":{"name":"Acta Cytologica","volume":" ","pages":"1-17"},"PeriodicalIF":1.6,"publicationDate":"2025-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143960304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Prognostic Significance of Ki-67 Expression in Breast Cancers Developing Malignant Effusions.","authors":"Ilias P Nikas, So Hyeon Yang, Sojung Lim, Hyebin Lee, Han Suk Ryu","doi":"10.1159/000546180","DOIUrl":"10.1159/000546180","url":null,"abstract":"<p><strong>Introduction: </strong>The aim of this study was to investigate the prognostic significance of Ki-67 in breast cancer patients developing malignant effusions.</p><p><strong>Methods: </strong>In this retrospective study, 76 breast cancer patients developing a malignant effusion were enrolled. The Ki-67 immunohistochemistry (IHC) findings from both initial tissue and paired metastatic effusion samples of these patients were grouped into the following three categories: ≤5, 6-29, and ≥30%.</p><p><strong>Results: </strong>Triple-negative breast cancer (TNBC) showed higher Ki-67 levels at both initial diagnosis (p < 0.001) and malignant effusion samples (p = 0.015), compared to the non-TNBC phenotypes at the same tumor evolution phases, respectively. A Ki-67 ≥30% at initial diagnosis was associated with a shorter overall survival (p = 0.031; long-rank test), in addition to an earlier development of a malignant effusion (p < 0.001; long-rank test). A Ki-67 ≤5% at malignant effusion cell block samples was associated with a longer post-effusion survival (p = 0.015; long-rank test). Lastly, a Ki-67 index ≤5% at the effusion samples showed a significantly lower risk of mortality following the development of malignant effusions (HR: 0.355 [0.150-0.842; p = 0.019]), after being adjusted for the intrinsic subtype covariate (TNBC vs. non-TNBC).</p><p><strong>Conclusion: </strong>Estimating the Ki-67 IHC expression in malignant effusion cytology samples may have a prognostic significance, when evaluating patients with metastatic breast cancer. However, larger scale prospective studies would be necessary to provide more evidence on this topic.</p>","PeriodicalId":6959,"journal":{"name":"Acta Cytologica","volume":" ","pages":"1-9"},"PeriodicalIF":1.6,"publicationDate":"2025-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143962215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cervicovaginal Infections and Coinfections and Their Significance through the Papanicolaou Test: A Cross-Sectional Study in Pregnant and Non-Pregnant Women.","authors":"Eder Yair Walttuoni Picón, Víctor Abraham Rojas Zumarán, Gloria Cruz-Gonzales, Rocio Lozada-Diaz, Cleofe Del Pilar Yovera-Ancajima","doi":"10.1159/000543839","DOIUrl":"10.1159/000543839","url":null,"abstract":"<p><strong>Introduction: </strong>Cervicovaginal infections continue to be a public health problem for the female population. The aim of this study was to compare the prevalence of infections and coinfections diagnosed by cervical cytology in pregnant and non-pregnant patients at the San Bartolomé Hospital, Lima, Peru.</p><p><strong>Methods: </strong>An observational and cross-sectional study was conducted. A sample of 284 cervical reports from pregnant and non-pregnant women was included and screened by the Pap test during the period 2021-2023.</p><p><strong>Results: </strong>The overall prevalence of cervicovaginal infections was 52.8%, for pregnant women 59.2% and for non-pregnant women 46.5%, with statistically significant differences between the groups (p < 0.05). Bacterial vaginosis (43%) and Candida spp. predominated (26.8%), showing significant differences (p < 0.05). No significant differences were observed with other cervicovaginal infections (p > 0.05). The general prevalence of coinfections was 13.4%, for the pregnant group it was 19.7% and for the non-pregnant group it was 7.0%, observing differences with statistical significance between the groups (p < 0.05). The most predominant coinfection was bacterial vaginosis accompanied by Candida spp. (13.4%), finding significant differences (p < 0.05). No significant differences were observed with other cervicovaginal coinfections (p > 0.05).</p><p><strong>Conclusion: </strong>There is a higher prevalence of cervicovaginal infections and coinfections in pregnant women in contrast to non-pregnant women, observing statistically significant differences by means of the Pap test.</p>","PeriodicalId":6959,"journal":{"name":"Acta Cytologica","volume":" ","pages":"1-8"},"PeriodicalIF":1.6,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143955291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Oncocytic Tumors in the Kidney: A Tri-Focal Review - Integrated Pathological, Cytopathological, and Molecular Perspectives, Part 2.","authors":"Laura Lanteri, Elena Luppi, Alessia Cimadamore, Gladell P Paner, José A Jiménez Heffernan, Giuseppe Gasparre","doi":"10.1159/000545946","DOIUrl":"10.1159/000545946","url":null,"abstract":"<p><strong>Background: </strong>This second of two parts review is devoted to the practical aspects of fine needle aspiration biopsy diagnosis of renal oncocytoma and the interesting biology underlying the morphologic transformation of oncocytes.</p><p><strong>Summary: </strong>In the first section, we describe the most useful cytologic variables for the recognition of oncocytoma since its first cytologic description 44 years ago. The usefulness of the recently introduced cytologic diagnostic category of \"low-risk oncocytic neoplasm\" is discussed, as well as the known problems of differential diagnosis. The second section deals with the molecular aspects of oncocytes, with special emphasis on correlating it with the peculiar morphology of oncocytic tumors and their less aggressive behavior. First, why does this accumulation of abnormal mitochondria occur, and second, what are the consequences? Regarding oxidative phosphorylation, oncocytes show a dysfunctional respiratory complex that makes them unable to respond adequately to the hypoxia so typical of the neoplastic environment.</p><p><strong>Key messages: </strong>The low-risk oncocytic neoplasm category is so relevant that they may limit the possibility of an accurate diagnosis in small specimens, such as FNA and core biopsies. However, this must be compatible with the possibility of making a useful diagnosis for the therapeutic management of the patient. Further, we discuss the genes and molecules responsible for mitochondrial dysfunction, and, finally, the molecular differences between sporadic oncocytomas and those associated with a hereditary context.</p>","PeriodicalId":6959,"journal":{"name":"Acta Cytologica","volume":" ","pages":"1-12"},"PeriodicalIF":1.6,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143962313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comprehensive Study of Thyroid Fine Needle Aspiration in Pediatric and Young Adults.","authors":"Erika F Rodriguez, Precious Ann V Fortes, Victoria Lee, Jeffrey D Goldstein, Neda A Moatamed","doi":"10.1159/000546006","DOIUrl":"10.1159/000546006","url":null,"abstract":"<p><strong>Introduction: </strong>Thyroid nodules are uncommon in the pediatric population, with a 1-1.7% prevalence. The Bethesda System of Reporting Thyroid Cytopathology (TBSTC) is a well-established thyroid fine needle aspiration (FNA) reporting system. While the TBSTC guides therapy for both adult and pediatric patients, the reported risk of malignancy (ROM) is variable in the literature. The aim of this study was to compare the ROM in pediatric age of <15 with ≥15 years old.</p><p><strong>Methods and materials: </strong>We searched for patients aged 21 or younger who underwent FNA of thyroid nodules from 2016 to 2021. Data included patient demographics, nodule size, FNA results, molecular results, and surgical pathology follow-up. Patients were divided into two cohorts: 0-14 (<15) and 15-21 (≥15) years old.</p><p><strong>Results: </strong>145 nodules from 102 patients (26 cases in <15 and 94 in patients ≥15) were analyzed. Diagnoses and ROM were nondiagnostic (n = 3), benign (108, ROM 50%), atypia of unknown significance (n = 13, ROM 67%), follicular neoplasm (n = 6, ROM 33%), suspicious for malignancy (n = 1, ROM 100%), malignant (n = 14, ROM 100%). No significant differences (p ≥ 0.2) between the age groups were noted. Based on surgical follow-up results, the overall malignancy rate was 8% and 19% for <15 and ≥15 years old groups, respectively.</p><p><strong>Conclusion: </strong>The ROM for thyroid nodules in the pediatric population is higher than in adults. There appears to be a trend toward a higher overall malignancy rate in patients aged 15-21 compared to those under 15, though this difference is not statistically significant. Further studies with larger patient numbers are required to determine if the ROM differs significantly between these age groups.</p>","PeriodicalId":6959,"journal":{"name":"Acta Cytologica","volume":" ","pages":"1-8"},"PeriodicalIF":1.6,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143965072","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diagnostic Performance of the Milan System for Reporting Salivary Gland Cytopathology and a Proposed Algorithm for Fine-Needle Aspiration Cytology of Salivary Gland Lesions.","authors":"Norihide Mochizuki, Hirotaka Fujita, Takuma Tajiri, Masataka Ueda, Makiko Kurata, Chie Inomoto, Tomoko Sugiyama, Daisuke Maki, Shuichi Shiraishi, Tomohisa Machida, Hitoshi Ito, Yohei Masugi, Naoya Nakamura","doi":"10.1159/000546005","DOIUrl":"10.1159/000546005","url":null,"abstract":"<p><strong>Introduction: </strong>We evaluated concordance between Milan System for Reporting Salivary Gland Cytopathology (MSRSGC)-based categorization of salivary gland masses/lesions screened by fine-needle aspiration cytology (FNAC) and final histopathologic diagnoses, aiming to identify factors predictive of concordance, with the goal of appropriate case management.</p><p><strong>Methods: </strong>The study was retrospective and involved 101 cases of salivary mass/lesion examined by FNAC. We compared MSRSGC categories against the final histopathologic classes (non-neoplasm, benign neoplasm, or malignant neoplasm) and calculated diagnostic concordance in each class. Concordance was defined as: MSRSGC categorization of a lesion as a category II lesion and a histopathologic classification as a non-neoplasm; MSRSGC categorization of a lesion as a category IV-A lesion and a histopathologic classification as a benign neoplasm; or MSRSGC categorization of a lesion as a category V or VI lesion and a histopathologic classification as a malignant neoplasm. We then compared clinicopathologic factors between concordant and discordant cases.</p><p><strong>Results: </strong>Diagnostic concordance for non-neoplasms, benign neoplasms, malignant neoplasms, and total cases was 81.8% (9/11), 81.7% (58/71), 66.6% (8/12), and 79.8% (75/94), respectively, with no significant between-class difference. We found the shortest distance from the body surface to the salivary lesion differed significantly between the concordant group and the discordant group (5.35 mm vs. 7.30 mm), and the optimal cutoff was determined to be 8.00 mm (p < 0.01).</p><p><strong>Conclusion: </strong>Based on the distance of either <8 mm or ≥8 mm from the body surface to the mass/lesion, we believe our proposed FNAC algorithm of treatment strategies is a reliable guide for otolaryngologists on evaluating salivary gland lesions.</p>","PeriodicalId":6959,"journal":{"name":"Acta Cytologica","volume":" ","pages":"1-12"},"PeriodicalIF":1.6,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143960999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Oncocytic Tumors in the Kidney: A Trifocal Review - Integrated Pathological, Cytopathological, and Molecular Perspectives (Part 1).","authors":"Alessia Cimadamore, Carmine Franzese, José A Jiménez Heffernan, Rodolfo Montironi, Jung Woo Kwon, Giuseppe Gasparre, Gladell P Paner","doi":"10.1159/000545812","DOIUrl":"10.1159/000545812","url":null,"abstract":"<p><strong>Background: </strong>We review the pathological, cytopathological, and molecular features centered on renal oncocytoma and its differential diagnosis. The recent expansion of entities under the category of renal tumors with oncocytic or eosinophilic cytoplasm has important implications on how cytologic diagnosis is clinically considered.</p><p><strong>Summary: </strong>In this first of two parts, we discussed the pathological spectrum of oncocytic or eosinophilic tumors of the kidney that includes oncocytoma; chromophobe renal cell carcinoma (ChRCC) - including its eosinophilic variant (eosinophilic ChRCC); hybrid oncocytic/chromophobe tumors, either sporadic or syndromic; oncocytic papillary RCC, acquired cystic disease-associated RCC; succinate dehydrogenase (SDH)-deficient RCC; and eosinophilic solid and cystic (ESC) RCC. We describe the histomorphological and immunohistochemical features of these tumors, including the newly accepted entities, and focus on the molecular alterations reported. A practical approach for differential diagnosis and broader correlation to available cytologic findings are provided, with more in-depth cytologic descriptions for oncocytoma and eosinophilic ChRCC included in part 2 of this review. Most of the oncocytic tumors have an indolent behavior, although few aggressive cases have been reported in patients with ESC RCC, eosinophilic vacuolated tumor, and SDH-deficient RCC.</p><p><strong>Key messages: </strong>In this era where surveillance management for low-grade oncocytic renal tumors is considered, precise diagnosis is important as it will have an impact on their subsequent management. Further, accurate diagnosis is important especially in renal tumors associated with hereditary neoplasms for monitoring and genetic counseling for their family members.</p>","PeriodicalId":6959,"journal":{"name":"Acta Cytologica","volume":" ","pages":"1-9"},"PeriodicalIF":1.6,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143954894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}