2025 Clinician Corner - Choreoathetosis as a rare complication of paraneoplastic syndrome: a case report in small cell lung cancer with positive anti-Hu antibodies

Abstract 

Choreoathetosis is a rare complication of paraneoplastic syndrome, particularly associated with small cell lung cancer. We report a case of an elderly woman with small cell lung cancer who was diagnosed with choreoathetosis due to autoimmune-mediated paraneoplastic syndrome. The differential diagnoses for focal neurological deficits such as stroke, immunotherapy-related toxicity, radiation-induced toxicity, and brain metastasis were considered but the presence of onconeural antibodies made paraneoplastic syndrome a more likely diagnosis. Management of choreoathetosis in paraneoplastic syndrome can be challenging, with limited treatment options available.  

Keywords:  anti-Hu antibodies; choreoathetosis; onconeural antibody; small cell lung cancer

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Faculty credentials/disclosure 

The planners and faculty for this activity have no relevant financial relationships to disclose. The patient consented to the publication of this report.

Process

Click the "add to cart/begin" button, pay any relevant fee, take the quiz, complete the evaluation, and claim your CME credit.  You must achieve 100% on the quiz with unlimited attempts available.

  • By completing this process, you are attesting that you have read the journal article.

Expiration date:

Credit eligibility for this article is set to expire on May 1, 2026.

Learning Objectives

After completing the article, the learner should be able to:

  • Recognize the potential differential diagnoses of paraneoplastic neurologic syndromes in patients with small cell lung cancer presenting with new focal neurological deficits, including movement disorders such as choreoathetosis. 
  • Evaluate current diagnostic and treatment strategies for paraneoplastic choreoathetosis, including immunomodulatory therapies like intravenous immunoglobulin, and tailor management plans to improve patient outcomes. 
  • Identify the role of anti-Hu antibodies and other onconeural antibodies in the diagnosis of paraneoplastic neurologic syndromes and understand their implications for managing neurologic complications in small cell lung cancer. 

Key Points 

  • The appearance of new focal neurological deficits in patients with small cell lung cancer should provoke evaluation for potential differential diagnoses, such as paraneoplastic syndrome or adverse effects related to cancer therapies including chemotherapy, immunotherapy, or radiation after ruling out acute treatable neurological conditions such as stroke, nutritional deficiencies, infections, and metabolic causes. 
  • Here we report a case of acute choreoathetosis related to positive anti-Hu paraneoplastic syndrome in a small cell lung cancer patient who had previously received multimodal treatment including chemotherapy, immunotherapy, and brain radiation. The diagnosis was made based on the time course of clinical manifestations, the timing and response to treatments received, laboratory work-up, and combined imaging studies.

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Course summary
Available credit: 
  • 1.00 American Board of Internal Medicine (ABIM) MOC Part 2
    Successful completion of this CME activity, which includes participation in the evaluation component, enables the participant to earn up to 1.00 MOC points in the American Board of Medicine’s (ABIM) Maintenance of Certification (MOC) program. It is the CME activity provider’s responsibility to submit participant completion information to ACCME for the purpose of granting ABIM MOC credit.
  • 1.00 American Board of Surgery (ABS) Accredited CME
    Successful completion of this CME activity enables the learner to earn credit toward the CME requirement of the American Board of Surgery’s Continuous Certification program. It is the CME activity provider's responsibility to submit learner completion information to ACCME for the purpose of granting ABS credit.
  • 1.00 AMA PRA Category 1 Credit™
    The A. Webb Roberts Center for Continuing Medical Education of Baylor Scott & White Health is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to provide continuing medical education for physicians.
  • 1.00 Attendance
Course opens: 
05/01/2025
Course expires: 
05/01/2026
Cost:
$25.00
Rating: 
0
  • Sakditad Saowapa, MD - Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas, USA 
  • Yaw Adu, MS - School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas, USA 
  • Kanak Parmar, MD - School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas, USA 
  • Veena Agusala - Department of Internal Medicine, Emory University, Atlanta, Georgia, USA  
  • Gwyn Srifuengfung, MD - Department of Neurology, Texas Tech University Health Sciences Center, Lubbock, Texas, USA  
  • Natchaya Polpichai, MD - Department of Internal Medicine Louis A Weiss Memorial Hospital, Chicago, Illinois, USA  
  • Pharit Siladech, MD - Internal Medicine Department, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand  
  • Manasawee Tanariyakul, MD - Department of Medicine, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA  

Accreditation

The A. Webb Roberts Center for Continuing Medical Education of Baylor Scott & White Health is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to provide continuing medical education for physicians.

Designation

AMA PRA Category 1 Credit™

The A. Webb Roberts Center for Continuing Medical Education of Baylor Scott & White Health designates this Journal-based CME activity for a maximum of 1.0 AMA PRA Category 1 Credit™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

ABS CC

Successful completion of this CME activity enables the learner to earn credit toward the CME requirement of the American Board of Surgery’s Continuous Certification program. It is the CME activity provider's responsibility to submit learner completion information to ACCME for the purpose of granting ABS credit.

ABIM MOC

 Successful completion of this CME activity, which includes participation in the evaluation component, enables the participant to earn up to 1.0 MOC points in the American Board of Internal Medicine’s (ABIM) Maintenance of Certification (MOC) program. It is the CME activity provider’s responsibility to submit participant completion information to ACCME for the purpose of granting ABIM MOC credit.

 

Available Credit

  • 1.00 American Board of Internal Medicine (ABIM) MOC Part 2
    Successful completion of this CME activity, which includes participation in the evaluation component, enables the participant to earn up to 1.00 MOC points in the American Board of Medicine’s (ABIM) Maintenance of Certification (MOC) program. It is the CME activity provider’s responsibility to submit participant completion information to ACCME for the purpose of granting ABIM MOC credit.
  • 1.00 American Board of Surgery (ABS) Accredited CME
    Successful completion of this CME activity enables the learner to earn credit toward the CME requirement of the American Board of Surgery’s Continuous Certification program. It is the CME activity provider's responsibility to submit learner completion information to ACCME for the purpose of granting ABS credit.
  • 1.00 AMA PRA Category 1 Credit™
    The A. Webb Roberts Center for Continuing Medical Education of Baylor Scott & White Health is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to provide continuing medical education for physicians.
  • 1.00 Attendance

Price

Cost:
$25.00
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