Paraneoplastic neurologic syndromes are disorders of the nervous system function caused by
cancer but not due to metastatic
disease, vascular or metabolic deficits,
infections, nutritive deficiency, nor side effects of
antineoplastic drugs or irradiation.
Immunologic factors probably play the crucial role in the pathogenesis of
paraneoplastic neurologic syndromes, but nonimmunologic mechanisms that include metabolic abnormalities and competition for substrate are also involved.
Paraneoplastic cerebellar degeneration most commonly occurs in the setting of gynecologic
cancers, but it accompanies the
small-cell lung cancer too. Other
tumors are infrequently associated with cerebellar degeneration. Several paraneoplastic
antibodies have been identified in patients with
paraneoplastic cerebellar degeneration. Their association with particular
cancers may help identify an occult lesion.
Anti-Yo antibodies are directed against Purkinje cell
antigens and occur in patients with cerebellar degeneration who have
breast cancer or gynecologic
tumors. A target
antigen of
anti-Yo antibody is CDR2
protein that is normally expressed only in the brain and testis. Patients with
paraneoplastic cerebellar degeneration present with
dizziness,
nausea and
vomiting followed by gait instability,
diplopia, gait and
appendicular ataxia,
dysarthria and
dysphagia. Therapeutic options include
tumor excision,
chemotherapy and/or irradiation, and adjuvant
therapy with
glucocorticoids,
immunoglobulins and
plasmapheresis. The role of
plasmapheresis in the treatment of
paraneoplastic cerebellar degeneration is still uncertain. Reports of its efficacy are anecdotal. We present patient with
paraneoplastic cerebellar degeneration with positive
anti-Yo antibodies and
tumor of the ovaries whose neurologic status significantly improved after four daily
plasmaphereses, which was accompanied by a fourfold decrease in the
anti-Yo antibodies titer. Further investigations are needed to define a protocol for
plasmapheresis in the treatment of patients with
paraneoplastic syndromes.