A case of Anti-Hu and Anti-Zic4 paraneoplastic cerebellar degeneration in a patient with stage IV adenocarcinoma of Müllerian origin.

Introduction: Paraneoplastic cerebellar degeneration (PCD) is a rare neurological complication of malignancies, resulting from autoimmune responses targeting antigens shared by neurons and tumors. It is characterized by progressive cerebellar dysfunction, including ataxia and dysarthria, and is associated with anti-onconeuronal antibodies such as Anti-Yo and Anti-Hu. While most cases of Anti-Hu-associated PCD occur in patients with small cell lung cancer, their association with gynecologic malignancies is exceedingly rare. This is the first reported case in the literature of a patient with adenocarcinoma of Müllerian origin complicated by Anti-Hu PCD. Case: We present the case of a 73-year-old female with stage IV adenocarcinoma of Müllerian origin who presented with worsening ataxia and dysarthria after undergoing outpatient chemoimmunotherapy to treat her gynecologic malignancy. CT and MRI Brain imaging revealed nonspecific findings, but cerebrospinal fluid (CSF) analysis revealed the presence of positive anti-Hu and anti-Zic4 antibodies, consistent with a diagnosis of PCD. Despite treatment with high-dose intravenous corticosteroids and plasmapheresis in the acute setting, the patient displayed minimal improvement and continued to experience persistent neurological impairment. Conclusion: Despite advancements in diagnostic criteria and the availability of multiple types of therapies, outcomes for PCD remain poor. This is especially notable for cases associated with Anti-Hu antibodies. This case highlights the importance of considering PCD in the differential diagnosis of patients with malignancies and unexplained neurological symptoms. Furthermore, it highlights the critical need for continued research to refine diagnostic methods and develop more effective, evidence-based treatment strategies to improve outcomes.