A case of small cell lung cancer with paraneoplastic neurological syndrome presenting as gait disturbance

A 58-year-old female patient was admitted to our hospital because of subacute progressive gait disturbance, dysarthria, dizziness, after flu-like symptoms. As autoimmune mechanism was considered, steroid pulse therapy and intravenous immunoglobulin therapy were performed. After giving immunosuppressive therapy, the neurologic symptom improved significantly. Chest CT revealed a swelling of the mediastinum lymph node, and small cell carcinoma was diagnosed with lymph node biopsy by transbronchial needle aspiration. PCD associated with small cell lung carcinoma was diagnosed, because no abnormalities were apparent in the examination of cerebrospinal fluid and Brain MRI. A complete response was achieved through chemotherapy and sequential radiotherapy, but the neurological symptoms were exacerbated during treatment. Intravenous immunoglobulin therapy was performed again, and the neurologic symptom improved. It is thought that not only antitumor therapy but combined use of immune therapy should be taken into consideration as a treatment choice in PCD.