Cancer-associated (especially small cell lung cancer (SCLC), limbic system (limbic encephalitis), brainstem (brainstem encephalitis), spinal cord (myelitis), or the entire neuraxis (encephalomyelitis). Acute to subacute onset classic antibody-mediated paraneoplastic encephalitis syndromes include anti-Hu encephalomyelitis (small cell lung cancer, SCLC), Ma2-associated encephalitis (testicular cancer), and anti-collapsin-responsive mediator protein-5 (CRMP5) encephalomyelitis (SCLC or thymoma). The gene discussed is PNMA2; the disease is viral encephalitis.