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    <Journal>
      <PublisherName>jmedicalcasereports</PublisherName>
      <JournalTitle>Frontiers in Medical Case Reports</JournalTitle>
      <PISSN>I</PISSN>
      <EISSN>S</EISSN>
      <Volume-Issue>Volume 7; Issue 3</Volume-Issue>
      <PartNumber/>
      <IssueTopic>Multidisciplinary</IssueTopic>
      <IssueLanguage>English</IssueLanguage>
      <Season>(May-Jun, 2026)</Season>
      <SpecialIssue>N</SpecialIssue>
      <SupplementaryIssue>N</SupplementaryIssue>
      <IssueOA>Y</IssueOA>
      <PubDate>
        <Year>-0001</Year>
        <Month>11</Month>
        <Day>30</Day>
      </PubDate>
      <ArticleType>Medical Case Reports</ArticleType>
      <ArticleTitle>Adult-Onset Still__ampersandsignrsquo;s Disease Presenting as FDG-Avid Lymphadenopathy Mimicking Lymphoma: A Diagnostic Pitfall in Pyrexia of Unknown Origin</ArticleTitle>
      <SubTitle/>
      <ArticleLanguage>English</ArticleLanguage>
      <ArticleOA>Y</ArticleOA>
      <FirstPage>1</FirstPage>
      <LastPage>8</LastPage>
      <AuthorList>
        <Author>
          <FirstName>Laura</FirstName>
          <LastName>Vahey</LastName>
          <AuthorLanguage>English</AuthorLanguage>
          <Affiliation/>
          <CorrespondingAuthor>N</CorrespondingAuthor>
          <ORCID/>
        </Author>
      </AuthorList>
      <DOI/>
      <Abstract>Adult-onset Still__ampersandsignrsquo;s disease is an uncommon systemic autoinflammatory condition that can present with non-specific clinical features and pose a significant diagnostic challenge. We report the case of a woman in her late 50s presenting with prolonged pyrexia of unknown origin, systemic inflammation, polyarthralgia, and an evanescent rash. Laboratory investigations revealed marked hyperferritinaemia (&gt;2000~__ampersandsignmicro;g/L), elevated inflammatory markers (C-reactive protein peaking at 266~mg/L), and neutrophilic leukocytosis. Extensive infectious and autoimmune investigations were negative. Positron emission tomography-computed tomography demonstrated widespread fluorodeoxyglucose-avid lymphadenopathy and splenic uptake, raising strong suspicion for lymphoma. However, subsequent ultrasound imaging revealed preserved nodal architecture, and biopsy was deferred. Following multidisciplinary evaluation, a diagnosis of late-onset adult-onset Still__ampersandsignrsquo;s disease was established using Yamaguchi criteria. The patient responded rapidly to corticosteroid therapy, with complete clinical and biochemical remission. This case highlights the diagnostic complexity of adult-onset Still__ampersandsignrsquo;s disease, particularly when presenting with PET-avid lymphadenopathy, and underscores the importance of integrating clinical, biochemical, and imaging findings to avoid misdiagnosis and unnecessary invasive procedures.</Abstract>
      <AbstractLanguage>English</AbstractLanguage>
      <Keywords>Adult-Onset Still's Disease,Pyrexia of Unknown Origin,FDG-PET,Diagnostic Dilemma,Yamaguchi Criteria,Lymphadenopathy</Keywords>
      <URLs>
        <Abstract>https://www.jmedicalcasereports.org/ubijournal-v1copy/journals/abstract.php?article_id=16223&amp;title=Adult-Onset Still__ampersandsignrsquo;s Disease Presenting as FDG-Avid Lymphadenopathy Mimicking Lymphoma: A Diagnostic Pitfall in Pyrexia of Unknown Origin</Abstract>
      </URLs>
      <References>
        <ReferencesarticleTitle>References</ReferencesarticleTitle>
        <ReferencesfirstPage>16</ReferencesfirstPage>
        <ReferenceslastPage>19</ReferenceslastPage>
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      </References>
    </Journal>
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