Chordoma is a rare tumor which develops from remnant notochord tissue. Sacro-coccygeal and spheno-occipital localizations predominate. We report a thoracic chordoma of the fifth thoracic vertebra with mediastinal expansion in a 70-year-old woman. Pathology confirmed the diagnosis revealing a lobulated architecture, presence of physaliphorous cells and intracellular mucoid substance. Immunohistochemistry can also be very helpful in atypical cases: positive for anti-cytokeratine, antivimetin and anti-protein S100 antibodies. Spontaneous outcome is fatal. Early and complete resection is the only way to improve prognosis.