Paraneoplastic neurologic syndromes.

Paraneoplastic neurologic disorders (PND) are remote medical complications of cancer that cannot be attributed to direct effects of the neoplasm or its metastases. PND are uncommon, disabling syndromes that have been recognized for more than 50 years. Despite their rarity, these diseases are the subject of intensive research and clinical fascination. This review highlights notable recent publications related to PND. In recent years, the broad clinical spectrum of PND has become even more apparent. PND can affect any part of the central or peripheral nervous system and often affect multiple areas simultaneously. These disorders are often associated with neuron-specific autoantibodies in the serum and cerebrospinal fluid. In clinical practice, detection of these antibodies is crucial for the diagnosis because the neurologic symptoms usually precede the diagnosis of cancer. Recent publications have described new antibody specificities associated with PND and expand our ability to identify patients serologically. Once diagnosed, detection of cancer can be difficult, but the use of positron emission tomography has been shown to be a useful supplement to standard imaging procedures. PND are thought to be autoimmune disorders precipitated by the immune response to cancer. Observations and laboratory studies in PND patients have shown that activation of cytotoxic T cells is an important component of the disease. These studies not only shed light on the pathogenesis of PND and the mechanisms of effective antitumor immunity but may eventually lead to improved treatment.