Paraneoplastic Syndromes

What Is Paraneoplastic Syndromes?

Paraneoplastic syndromes are a rare group of diseases that sometimes develop when there is cancer in the body. About 8-20% of people with cancer develop a type of PNS. Research has theorized that PNS develops when the immune system mistakenly attacks healthy nerve cells as a response to cancer in the body. More specifically, PNS is likely due to T-cells or other antibodies unintentionally attacking the nerve cells in the body when they are trying to attack the cancer (an autoimmune response).

There are multiple systems and organs in the body that PNS can affect, such as the nervous system, endocrine system (hormones), kidneys, bones, joints, skin, and blood. Often, paraneoplastic syndrome is the first sign of cancer. People have a greater likelihood of developing PNS if they are middle aged or older and have lung, lymphatic, ovarian, or breast cancer.

The types of paraneoplastic syndromes include:

  • Nervous system
  • Endocrine system (hormones)
  • Rheumatic (joints, bones, and muscles)
  • Hematologic (blood)
  • Dermatologic (skin)

Depending on what part of the nervous system is impacted by PNS, it may cause problems with movement, coordination, memory, cognition, sensory perception, and sleep. Damage to the nervous system can sometimes be healed or reversed once the cancer is treated and the immune system is functioning more appropriately.

However, in some instances, the damage from PNS happens so rapidly it becomes too severe to be reversed with treatment. Regardless, treatment interventions at any time may prevent further damage and allow for a better quality of life.

Signs and Symptoms

Symptoms of PNS vary depending on the system in the body that is impacted. About 60% of people who are diagnosed with PNS experience associated symptoms before a cancer diagnosis. Identifying symptoms of PNS can help your healthcare provider detect cancer in its earliest stages when it is more treatable.

Common symptoms of paraneoplastic syndrome include:

  • Fever
  • Night sweats
  • Loss of appetite
  • Weight loss 

Other symptoms vary depending on the organ system that is impacted:

Nervous system

  • Dizziness
  • Double vision
  • Memory loss
  • Speech difficulties
  • Seizures
  • Muscle weakness
  • Numbness in your arms and legs
  • Coordination issues (problems with reflexes and sensation) 

Endocrine (hormones)

  • Fatigue
  • High blood pressure
  • Nausea and vomiting
  • Unexplained weight gain
  • Muscle weakness 

Rheumatologic (joints, bones, and muscles)

  • Arthritis
  • Swelling and stiffness of the joints
  • Joint pain 

Dermatologic (skin)

  • Itching
  • Flushing
  • Thickened skin
  • Non-cancerous skin growths


The cause of paraneoplastic syndrome is due to an abnormal immune response. This abnormal immune response happens as a reaction to the immune system trying to attack the cancer cells, but instead, it inadvertently attacks the healthy nerve cells. Specifically, the immune system sends antibodies and t-cells to attack the cancer cells, but in the process, these agents also attack healthy cells throughout the body, causing paraneoplastic syndrome.

Additionally, some types of cancer secrete substances, such as hormones or proteins, that may impact the normal functioning of organs in the body. These substances can cause permanent damage without treatment.

Risk Factors

All types of cancer can be associated with paraneoplastic syndrome, but it is most common in lung, lymphatic, ovarian, and breast cancers. Additional risk factors include if you are middle aged and if you have a family history of cancer.


To diagnose paraneoplastic syndrome, your healthcare provider will evaluate your symptoms, perform a physical exam, and take a thorough medical history. Additionally, there are several tests your doctor will order. Tests include:

  • Neurological exam. Paraneoplastic syndrome impacts the nervous system, so your doctor will assess your brain functioning and look for any issues with movement or coordination.
  • Blood tests. These tests are useful at detecting abnormalities in the blood that would indicate cancer, paraneoplastic syndromes, or help to rule out other conditions that may be causing your symptoms (infection, metabolic disorder, or hormone disorder).
  • Imaging tests. Imaging tests such as MRI’s, CT scans, PET scan, or ultrasound can be used to detect cancer in the body.
  • Spinal tap (lumbar puncture). This procedure tests your cerebrospinal fluid for any signs of antibodies attacking healthy cells. 


The first line of treatment for paraneoplastic syndrome is to address the underlying cancer that is causing your symptoms. Secondarily, depending on what organ system is being impacted by PNS, your doctor may use immunosuppressants to reduce the production of antibodies that may be attacking healthy cells. Specific treatments include:

  • Corticosteroids. These types of medication (i.e., cortisone or prednisone) help to reduce inflammation or swelling throughout the body.
  • Immunosuppression. These types of medication help to suppress your body’s immune system and decreases the amount of antibodies attacking healthy cells. The type of medication used will be dependent upon what organ system is being impacted by PNS.
  • Intravenous immunoglobulin. This procedure injects healthy antibodies into the body and allows the healthy antibodies to attack and destroy the harmful antibodies that are causing paraneoplastic syndrome.
  • Plasmapheresis. This procedure removes plasma from the body that contains the antibodies that are attacking and harming healthy cells.
  • Physical therapy and speech therapy. These types of therapy can help improve issues with brain functioning and issues with movement and coordination. 


There is no known prevention for paraneoplastic syndrome. However, prevention measures that decrease your overall cancer risk may help to also reduce the risk of developing paraneoplastic syndrome. Prevention measures for cancer include:

  • Avoid tobacco and other smoking products
  • Limit exposure to certain toxins and chemicals
  • Regular exercise
  • Maintaining a healthy and balanced diet
  • Maintaining a healthy body weight
  • Knowing your family medical history 


Complications for paraneoplastic syndrome depend on the type of PNS and on the type of cancer associated with it. Complications may include:

  • Pneumonia or bacterial infection
  • Sepsis
  • (PNS with lung cancer) An autoimmune response that blocks that blocks air from passing through small airways in the lungs

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