Anti-Ri-associated paraneoplastic cerebellar degeneration without opsoclonus in a patient with a neuroendocrine carcinoma of the stomach.

We report a case of a 63-year-old man suffering from anti-Ri-associated paraneoplastic cerebellar degeneration (PCD) with gastric cancer. The neurologic presentation was limited to severe cerebellar ataxia without opsoclonus. The gastric cancer was composed of both poorly differentiated adenocarcinoma and neuro-endocrine carcinoma. The patient's serum reacted with recombinant Ri antigen and the neuroendocrine tumor component. It is thus considered that PCD without opsoclonus in the present case was related to the gastric neuroendocrine tumor and anti-Ri antibody.