Abstract
Paraneoplastic neurological syndrome (PNS) represents a rare group of central nervous system disorders that are unrelated to direct tumor invasion or metastasis but may be triggered by an immune system reaction to a neoplasm or malignant tumor. In many patients, PNS is diagnosed before identifying the primary cancer. In such instances, positron emission tomography/computed tomography scan can assess individuals with suspected PNS enabling the detection of hidden malignancies. We share an interesting image of paraneoplastic cerebellar degeneration in a case of invasive ductal carcinoma breast.