[Neurologic paraneoplastic syndromes and anti-neuronal antibodies]

A neurologic paraneoplastic syndrome may be the first sign of an occult and treatable cancer. Some syndromes are associated with autoantibodies against neuronal antigens. Patients with cerebellar degeneration and ovarian or breast cancer have antibodies against 34 and 62 kilodalton (kDa) proteins in Purkinje cell cytoplasm: anti-Yo antibodies. Patients with encephalomyelitis or sensory neuronopathy and small cell lung cancer have antibodies against 35-40 kDa neuronal nuclear proteins: anti-Hu antibodies. Patients with opsoclonus-myoclonus and breast cancer have antibodies against 55 and 80 kDa neuronal nuclear proteins: anti-Ri antibodies. Patients with Lambert-Eaton myasthenic syndrome and small cell lung cancer have antibodies against voltage-gated calcium channels (anti-VGCC) in motor nerve terminals. The presence of anti-neuronal antibodies strongly indicates that a neurological syndrome is paraneoplastic, and often identify the site of an occult neoplasm. However, the absence of detectable antibodies does not rule out the presence of an underlying tumour.