Background: Paraneoplastic cerebellar degeneration (PCD), one of the paraneoplastic neurological syndromes (PNS), develops a subacute cerebellar dysfunction and its neurological prognosis is poor in most cases. Because it is considered to be immune-mediated, immunosuppressive therapy may be effective, but its past outcomes are not constant.
Case: A 59-year-old woman presented with deteriorating cerebellar manifestations such as ataxic gait, nausea, and dysarthria. Chest CT revealed a nodule in the upper lobe of the right lung, and small cell lung cancer was diagnosed by transbronchoscopic lung biopsy and sputum cytology. Although known antineuronal antibodies were not detected, no other causative diseases were recognized, so PCD associated with SCLC was diagnosed. The cerebellar manifestations improved remarkably with immediate intravenous immunoglobulin (IVIG) therapy. SCLC showed complete response (CR) after chemoradiotherapy, and the neurological symptoms have not worsened at present.
Conclusion: Treatment with IVIG at the early stage may lead to the improvement of PCD and is worth attempting.