Rapidly Progressive Bilateral Leg Weakness in a 65-Year-Old Man: A Case Report

Paraneoplastic neurological syndromes can affect any part of the nervous system, often have a stereotypical presentation, occur in association with a tumor, and have an antibody-mediated pathogenesis. We describe the case of a 65-year-old previously healthy crane operator who presented to the emergency department due to symmetrical, gradually progressive gait instability and leg weakness. Due to evidence of a pulmonary mass in combination with polyneuroradiculopathy, a thoracoscopic upper lobe resection was performed with histological findings of an adenocarcinoma. Postoperatively, there was a marked improvement in gait and distal paraparesis. Despite an extensive search, no paraneoplastic autoantibodies could be detected in our patient. According to the 2021 consensus criteria, both the clinical phenotype and the presence of a tumor, as well as the determination of anti-neuronal antibodies in serum and cerebrospinal fluid, are essential for diagnosis. This enables a diagnosis to be made in four categories (definite, probable, possible, non-paraneoplastic neurological syndrome [PNS]). PEER REVIEWED ARTICLE Peer Reviewers: Prof. Dr Uwe Schlegel, Klinik für Neurologie Hirslanden, Zurich, und Neurozentrum Bellevue, Zurich One anonymous peer reviewer Received on January 25, 2025; accepted after peer review on February 27, 2025; published on March 17, 2025.