Paraneoplastic Cerebellar Degeneration

Paraneoplastic cerebellar degeneration (PCD) presents with acute or subacute onset of ataxia, dysarthria, and intention tremor. In patients older than 50 years, acute or subacute cerebellar degeneration is paraneoplastic in origin in 50% of cases. Paraneoplastic cerebellar degeneration most often precedes a potentially curable remote malignancy. Less often, PCD occurs in a patient with a known malignancy or heralds the onset of a recurrence. The presence of specific antibodies in serum samples helps to guide identification of the occult underlying malignancy. Physicians should entertain the diagnosis of PCD when older patients present with signs of cerebellar degeneration without an obvious cause. A systematic evaluation, including the selection of appropriate imaging and laboratory studies, will often enable physicians to identify the responsible cancer. However, because PCD can precede a cancer by months to years, periodic reevaluation is needed when the cancer remains occult.