Intradural extraosseous chordoma in the foramen magnum region. Case report.

Chordomas that are entirely extraosseous and intradural are extremely rare. The tumors described in the literature were observed mostly in the prepontine region. This is the first case reported of an intradural extraosseous chordoma occurring in the foramen magnum region. The tumor was totally excised. The distinction between an intradural extraosseous chordoma and a classic chordoma is important from a clinical viewpoint because of the potential for complete surgical excision and a more benign growth pattern.