Autoimmune encephalitis (AI) is a relatively newly defined group of noninfectious, immune-mediated inflammatory conditions of the brain parenchyma. First described in the 1960s, AI was originally found to be a paraneoplastic limbic encephalitis due to small cell lung cancer. A decade later research proved that this condition is caused by antibodies directed against either intracellular onconeuronal antigens, for example, anti-Hu or against the neuronal surface antigens, for example, anti-N-methyl-D-aspartate receptor (NMDAR). Most of the classic paraneoplastic autoimmune encephalitides belong to the former category.