Abstract
INTRODUCTION: Paraneoplastic neurological syndrome (PNS) was identified as a rare and unique clinical complication of primary tumors. Paraneoplastic cerebellar degeneration, a subtype of PNS, involved an immune-mediated attack on cerebellar Purkinje cells, resulting in a series of cerebellar symptoms. CASE PRESENTATION: We report a case of an elderly female patient who presented with subacute cerebellar symptoms, positive anti-YO antibody, and elevated CA-125 levels. Further examination revealed a fallopian tube malignancy. After surgery, intravenous immunoglobulin and glucocorticoid treatment, the oncological response was satisfactory, but the neurological symptoms did not improve. CONCLUSION: This case illustrates the importance of considering a paraneoplastic etiology in patients with unexplained neurological manifestations and emphasized the necessity of appropriate management and early treatment of the primary malignancy.