Archives of pathology & laboratory medicine最新文献

{"title":"Hypertrophic Lichen Planus: An Up-to-Date Review and Differential Diagnosis.","authors":"Carli P Whittington, Jasmine S Saleh, Scott C Bresler, Rajiv M Patel","doi":"10.5858/arpa.2022-0515-RA","DOIUrl":"10.5858/arpa.2022-0515-RA","url":null,"abstract":"<p><strong>Context.—: </strong>Hypertrophic lichen planus (HLP) is a variant of lichen planus that can be difficult to diagnose based on histopathologic features alone. Thus, patient clinical history and clinicopathologic correlation are essential considerations to make the correct diagnosis.</p><p><strong>Objective.—: </strong>To discuss the clinical and histologic presentation of HLP and provide a thorough review of commonly encountered mimickers in the differential diagnosis.</p><p><strong>Data sources.—: </strong>Data were derived from a literature review, personal clinical and research experiences, and a review of cases in the archives of a tertiary care referral center.</p><p><strong>Conclusions.—: </strong>In general, HLP involves the lower extremities and is characterized by thickened, scaly nodules and plaques that are often pruritic and chronic in nature. HLP affects both males and females and is most common in adults 50 to 75 years of age. Unlike conventional lichen planus, HLP tends to have eosinophils and classically displays a lymphocytic infiltrate most concentrated around the tips of rete ridges. The differential diagnosis for HLP is broad and encompasses numerous entities in many different categories, including premalignant and malignant neoplasms, reactive squamoproliferative tumors, benign epidermal neoplasms, connective tissue disease, autoimmune bullous disease, infection, and drug-related reactions. Therefore, a high index of suspicion must be maintained to avoid a misdiagnosis and potential inappropriate treatments.</p>","PeriodicalId":8305,"journal":{"name":"Archives of pathology & laboratory medicine","volume":" ","pages":"659-665"},"PeriodicalIF":3.2,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9640847","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":"Significant Variability in the Identification and Reporting of Band Neutrophils by Participants Enrolled in the College of American Pathologists Proficiency Testing Program: Time for a Change.","authors":"Maria Vergara-Lluri, Alexandra E Kovach, Megan O Nakashima, Kyle T Bradley, Etienne Mahe, Lawrence Tsao, Natasha M Savage, Stephanie A Salansky, Thomas Long, Sherrie L Perkins, Eric D Hsi, Olga Pozdnyakova, Parul Bhargava","doi":"10.5858/arpa.2023-0015-CP","DOIUrl":"10.5858/arpa.2023-0015-CP","url":null,"abstract":"<p><strong>Context.—: </strong>Increased band neutrophils in blood smear differential counts (\"bandemia\") are entrenched in medicine as a flag for sepsis. However, laboratory hematology experts have long advocated for discontinuation of reporting bands separately from segmented neutrophils because of poor sensitivity and specificity, poor interobserver agreement, and availability of alternative biomarkers for sepsis.</p><p><strong>Objective.—: </strong>To describe band neutrophil reporting practices and reproducibility of band classification among laboratories participating in the College of American Pathologists (CAP) proficiency testing (PT) program.</p><p><strong>Design.—: </strong>A survey questionnaire was distributed to hematology PT participants. A subsequent morphologic challenge included 12 preselected cell identifications of segmented neutrophils, bands, and metamyelocytes, and a 100-cell manual differential count of a digitally scanned blood smear.</p><p><strong>Results.—: </strong>Among laboratories that reported manual differentials, most respondents reported bands (4554 of 5268; 86.4%). Only 3222 of 4412 respondents (73.0%) provided band reference ranges. Though participants classified \"easy\" band neutrophils well (78.0%-98.3%), categorization of cell identifications for \"moderate\" and \"difficult\" bands was poor (3.1%-39.0% of laboratories), with classification instead as segmented neutrophils. This pattern was seen regardless of laboratory demographic characteristics. Marked variability in band counts was observed on the 100-cell differential count for both CAP PT participants and CAP Hematology and Clinical Microscopy Committee (HCMC) members (coefficients of variation, 55.8% and 32.9%, respectively). Variability was significantly improved when segmented and band neutrophils were grouped together (coefficients of variation, 6.2% and 5.0%, respectively).</p><p><strong>Conclusions.—: </strong>Most CAP PT-participating laboratories report band counts, many without reference ranges. The survey confirms significant interlaboratory variability of band enumeration when bands are separately identified from segmented neutrophils. This study reaffirms the CAP Hematology and Clinical Microscopy Committee's strong recommendation to group segmented and band neutrophils together in manual differential counts.</p>","PeriodicalId":8305,"journal":{"name":"Archives of pathology & laboratory medicine","volume":" ","pages":"666-676"},"PeriodicalIF":3.2,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10459259","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":"A Contemporary Approach to Intraoperative Evaluation in Neuropathology.","authors":"Nicole Becker, Sandra Camelo-Piragua, Kyle S Conway","doi":"10.5858/arpa.2023-0097-RA","DOIUrl":"10.5858/arpa.2023-0097-RA","url":null,"abstract":"<p><strong>Context.—: </strong>Although the basic principles of intraoperative diagnosis in surgical neuropathology have not changed in the last century, the last several decades have seen dramatic changes in tumor classification, terminology, molecular classification, and modalities used for intraoperative diagnosis. As many neuropathologic intraoperative diagnoses are performed by general surgical pathologists, awareness of these recent changes is important for the most accurate intraoperative diagnosis.</p><p><strong>Objective.—: </strong>To describe recent changes in the practice of intraoperative surgical neuropathology, with an emphasis on new entities, tumor classification, and anticipated ancillary tests, including molecular testing.</p><p><strong>Data sources.—: </strong>The sources for this review include the fifth edition of the World Health Organization Classification of Tumours of the Central Nervous System, primary literature on intraoperative diagnosis and newly described tumor entities, and the authors' clinical experience.</p><p><strong>Conclusions.—: </strong>A significant majority of neuropathologic diagnoses require ancillary testing, including molecular analysis, for appropriate classification. Therefore, the primary goal for any neurosurgical intraoperative diagnosis is the identification of diagnostic tissue and the preservation of the appropriate tissue for molecular testing. The intraoperative pathologist should seek to place a tumor in the most accurate diagnostic category possible, but specific diagnosis at the time of an intraoperative diagnosis is often not possible. Many entities have seen adjustments to grading criteria, including the incorporation of molecular features into grading. Awareness of these changes can help to avoid overgrading or undergrading at the time of intraoperative evaluation.</p>","PeriodicalId":8305,"journal":{"name":"Archives of pathology & laboratory medicine","volume":" ","pages":"649-658"},"PeriodicalIF":3.2,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10193903","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":"Pancreaticobiliary Cytology Practice in 2021: Results of a College of American Pathologists Survey.","authors":"Zaibo Li, Sana O Tabbara, Ann Nwosu, Rhona J Souers, Abha Goyal, Elizabeth M Kurian, Xiaoqi Lin, Christopher VandenBussche, Lananh N Nguyen","doi":"10.5858/arpa.2023-0167-CP","DOIUrl":"10.5858/arpa.2023-0167-CP","url":null,"abstract":"<p><strong>Context.—: </strong>The College of American Pathologists (CAP) surveys provide national benchmarks of pathology practice.</p><p><strong>Objective.—: </strong>To investigate pancreaticobiliary cytology practice in domestic and international laboratories in 2021.</p><p><strong>Design.—: </strong>We analyzed data from the CAP Pancreaticobiliary Cytology Practice Supplemental Questionnaire that was distributed to laboratories participating in the 2021 CAP Nongynecologic Cytopathology Education Program.</p><p><strong>Results.—: </strong>Ninety-three percent (567 of 612) of respondent laboratories routinely evaluated pancreaticobiliary cytology specimens. Biliary brushing (85%) was the most common pancreaticobiliary cytology specimen evaluated, followed by pancreatic fine-needle aspiration (79%). The most used sampling methods reported by 235 laboratories were 22-gauge needle for fine-needle aspiration (62%) and SharkCore needle for fine-needle biopsy (27%). Cell block was the most used slide preparation method (76%), followed by liquid-based cytology (59%) for pancreatic cystic lesions. Up to 95% (303 of 320) of laboratories performed rapid on-site evaluation (ROSE) on pancreatic solid lesions, while 56% (180 of 320) performed ROSE for cystic lesions. Thirty-six percent (193 of 530) of laboratories used the Papanicolaou Society of Cytopathology System for Reporting Pancreaticobiliary Cytology in 2021. Among all institution types, significant differences in specimen volume, specimen type, ROSE practice, and case sign-out were identified. Additionally, significant differences in specimen type, slide preparation, and ROSE practice were found.</p><p><strong>Conclusions.—: </strong>This is the first survey from the CAP to investigate pancreaticobiliary cytology practice. The findings reveal significant differences among institution types and between domestic and international laboratories. These data provide a baseline for future studies in a variety of practice settings.</p>","PeriodicalId":8305,"journal":{"name":"Archives of pathology & laboratory medicine","volume":" ","pages":"677-685"},"PeriodicalIF":3.2,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10215365","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":"Syphilis in Hematopathology Practice: A Diagnostic Challenge.","authors":"Efrain Gutierrez-Lanz, Lauren B Smith, Anamarija M Perry","doi":"10.5858/arpa.2023-0078-RA","DOIUrl":"10.5858/arpa.2023-0078-RA","url":null,"abstract":"<p><strong>Context.—: </strong>Syphilis, a reemerging disease caused by the spirochete Treponema pallidum, is becoming more frequent in surgical pathology and hematopathology practices. Hematopathologists typically receive lymph node biopsies from patients with syphilis who have localized or diffuse lymphadenopathy. Occasionally, syphilis infection in the aerodigestive tract can show a prominent lymphoplasmacytic infiltrate and mimic lymphoma. Besides the varying and occasional atypical morphology, the fact that clinical suspicion tends to be low or absent when histologic evaluation is requested adds to the importance of making this diagnosis.</p><p><strong>Objective.—: </strong>To summarize histologic features of syphilitic lymphadenitis and syphilis lesions in the aerodigestive tract, and to review differential diagnosis and potential diagnostic pitfalls.</p><p><strong>Data sources.—: </strong>Literature review via PubMed search.</p><p><strong>Conclusions.—: </strong>Characteristic histologic findings in syphilitic lymphadenitis include thickened capsule with plasma cell-rich inflammatory infiltrate, reactive follicular and paracortical hyperplasia with prominent lymphoplasmacytic infiltrate, and vasculitis. Lymph nodes, however, can show a number of other nonspecific histologic features, which frequently makes the diagnosis quite challenging. In the aerodigestive tract, syphilis is characterized by plasma cell-rich infiltrates. Immunohistochemistry for T pallidum is the preferred method for detecting spirochetes; however, this immunohistochemical stain shows cross-reactivity with other treponemal and commensal spirochetes. Differential diagnosis of syphilis in lymph nodes and the aerodigestive tract is broad and includes reactive, infectious, and neoplastic entities. Pathologists should be aware of the histologic features of syphilis and keep this challenging entity in the differential diagnosis.</p>","PeriodicalId":8305,"journal":{"name":"Archives of pathology & laboratory medicine","volume":" ","pages":"633-641"},"PeriodicalIF":3.2,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9933556","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":"Improving the Customer Experience: Physician Feedback Program for Clinical Laboratories.","authors":"Brian R Jackson, David Novis, Suzanne Coulter, Suzanne Dintzis, Barbara J Blond, Richard Brown","doi":"10.5858/arpa.2023-0064-CP","DOIUrl":"10.5858/arpa.2023-0064-CP","url":null,"abstract":"<p><strong>Context.—: </strong>Clinician feedback is an important source of information for laboratory quality improvement programs.</p><p><strong>Objective.—: </strong>To pilot a program for nearly real-time solicitation and analysis of physician feedback regarding clinical laboratory services.</p><p><strong>Design.—: </strong>Laboratories distributed either electronic or paper survey forms to physicians. Results were tabulated by College of American Pathologists staff. Free-text comments were shared promptly with the participating laboratories to facilitate follow-up.</p><p><strong>Results.—: </strong>Forty-seven clinical laboratories participated in the study and submitted results for 987 physician surveys, including both paper and electronic forms. Of 694 responses submitted electronically within the study period, 460 (66.3%) included at least 1 free-text entry, for a total of 951 free-text comments.</p><p><strong>Conclusions.—: </strong>Point-of-service solicitation of physician feedback regarding clinical laboratory services is feasible and can provide a substantial quantity of potentially useful information regarding laboratory performance from the customer perspective.</p>","PeriodicalId":8305,"journal":{"name":"Archives of pathology & laboratory medicine","volume":" ","pages":"694-698"},"PeriodicalIF":3.2,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10200797","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":"A Reassessment of the Impact and Significance of Social Media to Pathology.","authors":"Stephanie J T Chen, Megan I Samuelson, Anand Rajan Kd","doi":"10.5858/arpa.2022-0463-RA","DOIUrl":"10.5858/arpa.2022-0463-RA","url":null,"abstract":"<p><strong>Context: </strong>Social media (SM) use in pathology and medicine today is widespread, receives active advocacy, and is said to bring a host of benefits. In latter days, the harmful effects of SM have received attention, but they have yet been followed by greater encouragement of professionalized SM usage. SM use in medicine has seen adoption in parallel to its general ascendancy, even though the platforms are products with purposes misaligned with the practice of medicine.</p><p><strong>Objective: </strong>To (1) characterize premises and forces that propel professional SM platform adoption and use, and (2) examine wide-ranging literature, both medical and nonmedical, that substantiates the premises and to find counteracting perspectives and evidence.</p><p><strong>Data sources: </strong>Review of the literature using relevant keyword searches in PubMed, Google Scholar, Dimensions, and Web of Science for articles that study/describe professional SM use in pathology and medicine. Additionally, we examined business, technology, and social sciences literature and high-quality gray literature (newspapers, books, blogs) that addressed questions in relation to the topic of professional SM adoption.</p><p><strong>Conclusions: </strong>We identified 6 major premises as motivators of professional SM use and highlight significant counteracting factors. We conclude that the harms of professionalized SM use have not been fully considered in the medical literature and that a change in direction and the creation of new communication platforms would be beneficial.</p>","PeriodicalId":8305,"journal":{"name":"Archives of pathology & laboratory medicine","volume":" ","pages":"613-622"},"PeriodicalIF":3.2,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10101803","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 Implementation of Nongynecologic Reporting Systems in Cytopathology Laboratories Is Highly Variable: Analysis of Data From a 2020 Supplemental Survey of Participants in the College of American Pathologists Interlaboratory Comparison Program in Nongynecologic Cytology.","authors":"Christopher J VandenBussche, Ann Nwosu, Rhona Souers, Kaitlin E Sundling, Jennifer Brainard, Abha Goyal, Xiaoqi Lin, Shala Masood, Lananh Nguyen, Janie Roberson, Sana O Tabbara, Christine Booth","doi":"10.5858/arpa.2023-0010-CP","DOIUrl":"10.5858/arpa.2023-0010-CP","url":null,"abstract":"<p><strong>Context: </strong>In recent years, several reporting systems have been developed by national and international cytopathology organizations to standardize the evaluation of specific cytopathology specimen types.</p><p><strong>Objective: </strong>To assess the current implementation rates, implementation methods, and barriers to implementation of commonly used nongynecologic reporting systems in cytopathology laboratories.</p><p><strong>Design: </strong>Data were analyzed from a survey developed by the College of American Pathologists Cytopathology Committee and distributed to participants in the College of American Pathologists Nongynecologic Cytopathology Education Program mailing.</p><p><strong>Results: </strong>Nongynecologic reporting systems with the highest rate of adoption were the Bethesda System for Reporting Thyroid Cytopathology, 2nd edition (74.1%; 552 of 745); the Paris System for Reporting Urinary Cytology (53.9%; 397 of 736); and the Milan System for Reporting Salivary Gland Cytopathology (29.1%; 200 of 688). The most common reason given for not adopting a reporting system was satisfaction with a laboratory's current system. Implementation varied among laboratories with regard to which stakeholders were involved in deciding to implement a system and the amount of education provided during the implementation process.</p><p><strong>Conclusions: </strong>The implementation of nongynecologic reporting systems in cytopathology laboratories was highly variable.</p>","PeriodicalId":8305,"journal":{"name":"Archives of pathology & laboratory medicine","volume":" ","pages":"531-537"},"PeriodicalIF":3.2,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10096357","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":"Correlation of Red Blood Cell Casts With Renal Dysfunction in Patients With Infection-Related Glomerulonephritis.","authors":"Mineaki Kitamura, Laura Biederman, Dalia Ibrahim, Tibor Nadasdy, Sergey V Brodsky, Anjali A Satoskar","doi":"10.5858/arpa.2022-0514-OA","DOIUrl":"10.5858/arpa.2022-0514-OA","url":null,"abstract":"<p><strong>Context: </strong>Infection-related glomerulonephritis (IRGN) usually manifests as a proliferative immune-complex glomerulonephritis. The degree of renal dysfunction at presentation can vary. Association with histologic features on kidney biopsy remains unknown.</p><p><strong>Objective: </strong>To study the correlation between renal function in IRGN at the time of biopsy and the severity of histologic features.</p><p><strong>Design: </strong>Culture-proven IRGN cases at our facility were included and divided based on estimated glomerular filtration rate (eGFR) 15 ml/min/1.73 m2. Patients' demographic and pathologic findings were obtained from electronic medical records and kidney biopsy reports.</p><p><strong>Results: </strong>In total, 104 cases were diagnosed with IRGN on biopsy (mean age, 55.6 ± 15.6 years; male, n = 79 [76%]; median eGFR, 14.5 mL/min/1.73 m2), and 51 of 104 showed eGFR <15 mL/min/1.73 m2. Among all the histologic features assessed, only percent tubules with red blood cell (RBC) casts showed statistical difference, being significantly higher in the lower-eGFR group (P = .004). Multivariable logistic regression analysis also showed that %tubules with RBC casts were associated with lower eGFR (odds ratio, 1.12; 95% CI, 1.01-1.24; P = .01). Patients with 5% or more RBC casts (n = 31) showed a lower eGFR (P = .02) and a higher %cellular crescent (P < .001) compared with those with less than 5% RBC casts. Patients with concomitant anticoagulant therapy (n = 11) showed higher percentages of RBC casts than those without anticoagulants (P = .02).</p><p><strong>Conclusions: </strong>Particular attention to the extent of RBC casts on kidney biopsy is recommended in patients with IRGN because these portend worse renal dysfunction, more so in patients requiring anticoagulation (including for hemodialysis) because they are especially vulnerable to developing anticoagulant-related nephropathy.</p>","PeriodicalId":8305,"journal":{"name":"Archives of pathology & laboratory medicine","volume":" ","pages":"545-552"},"PeriodicalIF":3.2,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10124079","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":"Atypical Droplet Digital Polymerase Chain Reaction Patterns That Indicate Uncommon but Clinically Actionable EGFR Mutations in Lung Cancer.","authors":"Adam Lechner, Anooja Rai, Vanesa Rojas-Rudilla, Yanan Kuang, Cloud P Paweletz, Lynette M Sholl, Fei Dong","doi":"10.5858/arpa.2023-0088-OA","DOIUrl":"10.5858/arpa.2023-0088-OA","url":null,"abstract":"<p><strong>Context: </strong>Droplet digital polymerase chain reaction (ddPCR) is a sensitive method to detect common pathogenic EGFR mutations in non-small cell lung cancer. Although targeted assays have not been specifically designed to detect them, uncommon EGFR mutations have been linked to response to targeted therapy.</p><p><strong>Objective: </strong>To describe atypical ddPCR patterns that correspond to uncommon but clinically actionable EGFR mutations.</p><p><strong>Design: </strong>A cohort of 1134 consecutive non-small cell lung cancers that underwent targeted next-generation sequencing was reviewed. Uncommon EGFR mutations involving probe binding sites were evaluated by ddPCR.</p><p><strong>Results: </strong>Two hundred fifty-five of 1134 cancers (22.5%) harbored pathogenic EGFR mutations. One hundred eighty-six of 255 (72.9%) had canonical EGFR exon 19 deletion or exon 21 p.L858R variants designed for detection by ddPCR. An additional 25 of 255 cases (9.8%) had uncommon EGFR mutations within the probe-binding site, including 1 case with concurrent uncommon mutations in both exon 19 and exon 21. These mutations included uncommon EGFR exon 19 deletions (n = 6), EGFR exon 19 substitutions p.L747P (n = 3) and p.L747A (n = 1), dinucleotide substitutions leading to EGFR p.L858R (n = 5), EGFR exon 21 substitutions p.K860I (n = 1) and p.L861Q (n = 9), and EGFR p.[L858R;K860I] (n = 1). Droplet digital polymerase chain reaction generated atypical but reproducible signal for each of these uncommon variants.</p><p><strong>Conclusions: </strong>Droplet digital polymerase chain reaction analysis of uncommon pathogenic EGFR variants can yield unique and reproducible results. Recognition of atypical patterns in EGFR ddPCR testing can prompt confirmatory molecular testing and aid appropriate targeted therapy selection for patients with non-small cell lung cancer.</p>","PeriodicalId":8305,"journal":{"name":"Archives of pathology & laboratory medicine","volume":" ","pages":"553-558"},"PeriodicalIF":3.2,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10483879","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}