Paraneoplastic Neurological Syndromes (PNS) are rare remote effects of cancer, not directly attributed to mass lesions, metastases, infections, ischemia, coagulopathy, metabolic disruptions or tumour treatment. Currently, PNS treatment is mostly limited to tumour treatment. Because of an initial inflammatory stage early in the evolution of the PNS several immunotherapy modalities have been tried. Intravenous human immunoglobulins could be expected to provide a stabilization or even improvement of PNS, if administered early enough to prevent permanent neuronal damage.