A paraneoplastic syndrome marked by degeneration of neurons in the limbic system. Clinical features include hallucinations, loss of EPISODIC memory; ANOSMIA; ageusia; temporal lobe epilepsy; dementia; and affective disturbance (depression). Circulating anti-neuronal antibodies (e.g., anti-Hu; anti-Yo; anti-Ri; and anti-Ma2) and small cell lung carcinomas or testicular carcinoma are frequently associated with this syndrome.