Primary intradural chordoma: report on three cases and review of the literature.

Objective: Chordomas are rare malignant bone tumors of the skull base or sacrococcygeal region. They derive from notochordal remnants and usually have a chronic progressive course. Even rarer, intradural chordomas with a better biological behavior have also been reported. We present 3 further primary intradural extraosseous chordomas with a favorable clinical outcome. Clinical presentation: Two patients, a 38-year-old man and a 44-year-old woman, presented with neck pain. In these, intradural extra-spinal tumors within intervertebral foramina were found. Both tumors were totally removed and the patients have been free of disease for 7 years and 1 year, respectively. The other patient, a 76-year-old man suffered from an unspecific gait disorder and diplopia as a result of a prepontine space-occupying lesion. In this case, only an incomplete tumor resection was possible but progression has not occurred for 5 years. Materials and methods: Paraffin blocks from all cases were examined with classical histopathological stainings and immunohistochemistry for pancytokeratin, CK7, CK8/18, CK19, EMA, CEA, vimentin, S100, aktin, desmin, GFAP, CD117, PDGF-receptor alpha and beta, collagen-type-IV, p63, and Ki67. Fluorescent in situ hybridization was used to exclude EWS translocation. Results: All cases showed the typical histological picture with physaliphorous cells in a myxoid matrix and the characteristic immunohistochemical profile with positivity for vimentin, pancytokeratin, CK19, EMA, and S100. Staining for P63 and type IV collagen was consistently negative. Myxoid extraskeletal chondrosarcoma was excluded by in-situ-hybridization of the EWS gene. Conclusion: Considering our cases in context with so far published literature, we conclude that intradural chordomas are rare and in this location usually have a better prognosis compared to classical intraosseous chordomas.