Early-onset immunotherapy by intravenous immunoglobulin and corticosteroids in well characterized onconeural-antibody-positive paraneoplastic neurological syndrome.

Abstract

Paraneoplastic neurological syndromes (PNS) are defined as immune mediated disorders, potentially affecting the whole nervous system, and are often associated with cancer 1. Some clinical patterns are highly frequent in these syndromes, such as paraneoplastic cerebellar degeneration (PCD), limbic encephalitis (LE), subacute sensory neuronopathy (SSN) and Lambert–Eaton myasthenic syndrome (LEMS) 1. In the 1980s, antibodies targeting intracellular neuronal proteins were described as biomarkers of PNS 1, advocating an underlying tumour. Indeed, more than 90% of patients with such antibodies suffered from an associated cancer. Recently, patients with a similar clinical presentation to PNS have been reported with other autoantibodies targeting cell-surface synaptic antigens. An associated cancer is less frequent in these patients. These findings have changed the concept of PNS 2, and the new PNS classification is now based on the location of the targeted antigen, instead of being defined by clinical symptoms or oncological status.