Paraneoplastic cerebellar degeneration is a paraneoplastic phenomenon associated with lung, ovarian, breast, and other cancers. It is believed to be due to an autoimmune reaction targeted against components of the central nervous system (specifically Purkinje cells and large brain stem nuclei). It is thought to be caused by an anti-neuronal antibody known as anti-Yo but in lung paraneoplastic cerebellar degeneration, it is thought to be caused by antibody called "anti-Hu". One of the better characterized paraneoplastic neurologic syndrome is cerebellar ataxia caused by Purkinji cell drop-out in the cerebellum; it is manifested by dysarthria, limb and gait ataxia, and nystagmus...