[Notochordal tumors : Benign notochordal tumors and chordomas].

Benign notochordal tumors (BNCT) and chordomas are primary bone tumors of the spine with a predominant localization in the sacrum and clival region followed by the vertebral bodies. Besides the most common variant (NOS [not otherwise specified] with hepatoid or renal carcinoma cell-like differentiation) chordomas with chondroid, and polymorphic to anaplastic morphology are described. An unfavorable variant are pediatric chordomas with a loss of INI-1. BNCT and chordomas are characterized by the following immunohistological profile: vimentin+, cytokeratin+/-, epithelial membrane antigen (EMA)+/-, S100 protein+/-, brachyury+. This profile helps to distinguish these tumors from other lesions such as chondrosarcoma, chordoid meningioma, and metastases of carcinoma.