Paraneoplastic syndromes involving the nervous system

The term paraneoplastic syndromes refers to symptoms or signs resulting from damage to organs or tissues that are remote from the site of a malignant neoplasm or its metastases. Paraneoplastic syndromes can affect most organs and itssues. The paraneoplastic syndromes are rare, affecting less than 1/10,000 patients with cancer, only the Lambert-Eaton myasthenic syndrome is relatively frequent, occurring in about 1% of patients with small cell lung cancer. The paraneoplastic syndromes can affect any part of the central and peripheral nervous system. They can be isolated or in association.This suggested that those disorders are immune-mediated, but the antibodies and cytotoxic T-cells that are specific for the tumor antigen are not sufficient to cause neurologic disease unless they cross the blood brain barrier and react with neurons expressing the onconeural antigen.The histologic features of tumors in paraneoplastic neurologic disorders do not differ from those of other tumors, except that the tumors may be heavily infiltrated with inflammatory cells.