Anti-Yo-associated paraneoplastic cerebellar degeneration in a man with gastric adenocarcinoma.

Paraneoplastic cerebellar degeneration (PCD) with anti-Yo antibodies is almost always associated with ovarian and breast cancer. We describe a man with anti-Yo-positive PCD and gastric adenocarcinoma. The tumor cells were labeled with anti-Yo antibodies by immunohistochemistry. High serum titers of anti-Yo antibodies were found before surgery and decreased 6 months after resection of the tumor. The expression of Yo antigens by the tumor and the decrease in anti-Yo antibody titers after its removal suggest that the immune response against the Purkinje cells of the cerebellum was triggered by the tumor.