Intradural-Extramedullary Metastatic Tumor from Lung Cancer-A Case Report and Review

A 62-year-old male presented with a thoracic intradural-extramedullary metastasis from lung cancer. He complained of walking difficulty and bilateral lower leg numbness. He had a past history of lung adenocarcinoma three years prior. Thoracic spine magnetic resonance imaging showed that the tumor occupied the right subarachnoid space and spinal nerve roots had shifted to the left side at Th12. He was diagnosed with cauda equina syndrome by an intradural-extramedullary tumor. Surgery was performed (Th12 laminectomy) and we opened the dura mater and arachnoid membrane. The tumor was in the right side and was removed. After the operation, his neurological condition soon improved and he could walk with a cane. By four moths postoperatively, a metastatic brain tumor occurred and he had to use a wheel chair. He died one year after surgery. Immunohistochemical staining was positive for thyroid transcription factor-1 in both the lung adenocarcinoma and intradural-extramedullary tumor. We diagnosed a metastatic tumor. Including the present case, 102 cases of a metastatic intradural-extramedullary tumor have been reported and, thus, the condition may not be rare. In more than twenty years there have only been two case studies, which recommended both operative and non-operative methods. We reviewed the validity of an operation base on the prognosis and surgical results of previous reports. The average life expectancy was 8.6 months. The functional improvement rate was 78%. We recommend an operation for an intradural-extramedullary metastatic tumor because it improves the quality of a patients’ short life.