Imaging in paraneoplastic neurological syndromes: a comprehensive review

Paraneoplastic neurological syndromes (PNS) are a complex spectrum of clinical syndromes that are associated with underlying malignancies. Majorly being immune-mediated, these syndromes are characterized by the presence of specific paraneoplastic antibodies that are either directed against intracellular (onconeuronal) or extracellular (surface or junctional) antigens. Syndromes associated with the occurrence of onconeuronal antibodies have poor prognoses. The spectrum of neurological manifestations includes limbic encephalitis, paraneoplastic cerebellar degeneration, rhombencephalitis, myelitis, optic neuropathy, cranial neuropathies, plexopathy and polyneuropathy. This review presents a comprehensive overview of these manifestations including their imaging features, associated malignancies and antibodies, differential diagnoses and recommended further evaluation.