Paraneoplastic neurologic disorders
are a group of rare degenerative conditions that are triggered by a person's immune system response to a cancerous tumor. Researchers believe these disorders occur when cancer-fighting antibodies or white blood cells known as T cells mistakenly attack normal cells in the nervous system. Paraneoplastic neurologic disorders typically develop after mid-adulthood and are most common in people with lung, ovarian, lymphatic, or breast cancer. Symptoms generally develop over a period of days to weeks and usually occur prior to tumor detection. These symptoms may include difficulty in walking and/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, and vertigo. Paraneoplastic neurologic disorders include Lambert-Eaton myasthenic syndrome, stiff-person syndrome, encephalomyelitis (inflammation of the brain and spinal cord), myasthenia gravis, cerebellar degeneration, limbic and/or brainstem encephalitis, neuromyotonia, and opsoclonus (involving eye movement) and sensory neuropathy. Source: Genetic and Rare Diseases Information Center (GARD), supported by ORDR-NCATS and NHGRI.