Paraneoplastic Syndromes

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What are paraneoplastic syndromes?

Paraneoplastic syndromes are a group of rare disorders that occur when the immune system has a reaction to a cancerous tumor known as a "neoplasm."

The immune system is very important in keeping you healthy. It consists of cells, tissues, and organs that work together to help your body fight infections and other diseases. Scientists think paraneoplastic syndromes happen when cancer-fighting antibodies or white blood cells (known as T cells) mistakenly attack normal cells in the nervous system.

Paraneoplastic syndromes are most common in middle-aged or older adults. They more commonly occur in people with lung, ovarian, lymphatic, or breast cancer. These symptoms normally start before a tumor, or cancer-filled growth, is found. They slowly develop over a few days or weeks. Symptoms include:

  • Difficulty walking or swallowing
  • Loss of muscle tone
  • Loss of fine motor coordination
  • Slurred speech
  • Memory loss
  • Vision problems
  • Sleep disturbances
  • Dementia
  • Seizures
  • Sensory loss in the limbs
  • Vertigo or dizziness

Paraneoplastic syndromes include:

  • Lambert-Eaton Myasthenic Syndrome
  • Stiff-Person Syndrome
  • Encephalomyelitis
  • Myasthenia Gravis
  • Cerebellar Degeneration
  • Limbic or Brainstem Encephalitis
  • Neuromyotonia
  • Opsoclonus
  • Sensory Neuropathy

Treatment of paraneoplastic syndromes focuses on taking care of any tumor or cancer that is found in the body, followed by efforts to decrease the autoimmune response.

Plasmapheresis, a process that cleanses antibodies from the blood, may ease symptoms in people with paraneoplastic disorders that affect the peripheral nervous system. Speech and physical therapy may help individuals regain some functions.

There is no cure for paraneoplastic syndromes, and treatment will not stop neurological damage. The stage of cancer when diagnosed will determine the outcome of paraneoplastic syndromes.

Learn About Clinical Trials
Clinical trials are studies that allow us to learn more about disorders and improve care. They can help connect patients with new and upcoming treatment options.

How can I or my loved one help improve care for people with a paraneoplastic syndrome?

Consider participating in a clinical trial so clinicians and scientists can learn more about paraneoplastic syndromes and related disorders. Clinical research uses human volunteers to help researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.

All types of volunteers are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities to ensure that study results apply to as many people as possible, and that treatments will be safe and effective for everyone who will use them.

For information about participating in clinical research visit NIH Clinical Research Trials and You. Learn about clinical trials currently looking for people with paraneoplastic syndromes at

Where can I find more information about paraneoplastic syndromes?

Information may be available from the following organizations:

National Cancer Institute (NCI)
Phone: 800-422-6237 or 800-332-8615 

National Organization of Rare Disorders (NORD)
Phone: 203-744-0100 or 800-999-6673; 844-259-7178 Spanish

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