Antineuronal autoantibodies in paraneoplastic cerebellar degeneration associated with adenocarcinoma of the prostate

Paraneoplastic neurological syndromes are unusual in prostatic cancer, and paraneoplastic cerebellar degeneration associated with adenocarcinoma of the prostate is rare. Here we report a 68 year old man who developed progressive ataxia in the setting of stage D2 adenocarcinoma of the prostate and whose MRI showed cerebellar atrophy. The patient's serum produced a previously undescribed pattern of immunoreactivity, binding to nuclei and cytoplasm of Purkinje cells, deep cerebellar neurons, scattered cells in the molecular and granule cell layers, and neuronal populations in thalamus, cerebral cortex, and hippocampus but not with liver or kidney. The patient's IgG also labeled a 65 kDa protein, discrete from Yo antigen, in Western blots of Purkinje cell lysates and did not react with blotted recombinant HuD, Ri, Yo, or amphiphysin proteins. Sera from neurologically normal patients with adenocarcinoma of the prostate did not contain this antibody, and the patient's serum did not react with normal prostate or with prostatic adenocarcinomas from other individuals. Prostatic adenocarcinoma may occasionally be accompanied by development of anticerebellar antibodies. Adenocarcinoma of the prostate should be considered as a possible underlying malignancy in older males with unexplained progressive cerebellar degeneration.