Intradural extramedullary metastasis: a review of literature and case report

Introduction: Intradural extramedullary (IDEM) metastatic disease is infrequently encountered by spine surgeons and consequently poorly understood. Discovery often corresponds with the onset of neurologic symptoms and no consensus exists regarding the importance of complete resection or anticipated postoperative outcome. We aim to elucidate treatment methodologies that exist in the literature. Case presentation: We present a unique case of a 57-year-old male with a known history of esophageal adenocarcinoma, including brain and visceral metastases, who presented with cauda equina syndrome. An IDEM metastatic esophageal adenocarcinoma lesion was identified on advanced imaging and biopsy. This was treated operatively without return of neurologic function. Discussion: We reviewed and summarized the existing literature. Trends are highlighted to further guide surgeons treating this unusual metastatic phenomenon. Conclusion: Intradural metastasis is a harbinger of advanced disease with a poor prognosis regardless of the etiology of the primary lesion. There are a number of proposed mechanisms for metastatic spread with little available literature for surgeon guidance. Most authors are advocates of a palliative, decompressive approach.