Paraneoplastic cerebellar degeneration.

Paraneoplastic cerebellar degeneration is a rare complication of a number of cancers, particularly small cell lung cancer, gynecologic cancers and Hodgkin's disease. The disorder is clinically characterized by rapid development of pancerebellar dysfunction, which usually does not improve, and pathologically characterized by loss of Purkinje cells with or without inflammatory infiltrates. In some but not all patients, an autoantibody that reacts with the tumor and Purkinje cells can be found in the serum and spinal fluid of patients with paraneoplastic cerebellar degeneration. The presence of the autoantibody suggests, but does not prove, that the disorder has an autoimmune mechanism for its pathogenesis.