Background: Paraneoplastic syndromes have been associated with certain malignancies, classically with small cell lung cancer. However, there have been case reports of solid tumors that have been associated with paraneoplastic syndromes as well. This is believed to be the first case that details a young man with Ewing sarcoma who developed Guillain-Barre Syndrome in the form of a paraneoplastic syndrome. Case Presentation: A 23-year-old man with localized Ewing sarcoma presented to the hospital with weakness. He was initially treated with interval compressed chemotherapy and radiation, but developed recurrence and underwent hemipelvectomy. He had chronic numbness of his extremities from vincristine that felt acutely worsened over several days prior to admission. Additionally, he was now having difficulty grasping objects and walking. His exam was notable for mildly decreased strength in his lower extremities but preserved in his upper extremities along with intact extraocular movements. The following morning he was unable to move and lost all sensation in his left lower extremity along with new dysphagia. Urgent work-up revealed a normal MRI brain, MRI spine with enhancement of cauda equina nerve roots around the conus, and a lumbar puncture with cytoalbuminologic dissociation. Ultimately was diagnosed with presumed Guillain-Barre Syndrome and treated with IVIG. Conclusion: Guillain-Barre is a rare but serious syndrome that needs to be recognized quickly given its high mortality and morbidity rate and necessity of quick intervention. It is imperative for clinicians to maintain a high degree of clinical suspicion as a manifestation of paraneoplastic syndrome from malignancies.
