Anti-Yo Mediated Paraneoplastic CerebellarDegeneration Associated with Pseudobulbar Affectin a Patient with Breast Cancer

Paraneoplastic cerebellar degeneration (PCD) is a rare anti-Yo mediated paraneoplastic syndromes rarely that is infrequentlyassociated with breast cancer. We present a case of a 52-year-old female presenting with diplopia, gait instability, dysarthria,dysphagia, nystagmus, and, most notably, new onset paroxysmal episodes of uncontrollable crying concerning for pseudobulbaraffect (PBA). Serologic testing showed anti-Yo antibodies. The patient was found to have stage IIIA breast cancer as the inciting causeof the paraneoplastic syndrome. The patient was treated with neoadjuvant chemotherapy, modified radical mastectomy, adjuvantHerceptin, and pertuzumab. She was given IVIG for paraneoplastic syndrome, antidepressants, and dextromethorphan-quinidine(Nuedexta), the first FDA-approved therapy for PBA. With multimodality therapy, she demonstrated significant improvement inneurologic and mood symptoms associated with PCD and PBA.