Intradural chordoma of the Meckel's cave: A challenging differential diagnosis.

Chordomas are midline tumors that arise from embryonic remnants of the notochord and are considered to be malignant tumors because of their tendency to invade and destroy the involved bone. Cases of intradural chordomas without bone involvement have been rarely described with a predilection for prepontine location. The absence of bony invasion renders the complete excision of these tumors more feasible and is related to their better prognosis in comparison to conventional chordomas. Herein we report the first intradural chordoma arising in the Meckel's cave. The intradural location of the lesion, outside midline structures, in the absence of bone infiltration, made the differential diagnosis versus other meningeal lesions such as chordoid meningioma challenging. The intense and strong immunohistochemical expression of pan-cytokeratins, S100, cytokeratin-19 and of the notochordal marker brachyury allowed differential diagnosis toward other tumors showing chordoid morphology. The expression of brachyury, which had not been previously analyzed in intradural chordoma, definitely links the histogenesis of this neoplasia to the notochord, similar to that of conventional chordoma. We also show that, different from conventional chordoma, intradural chordoma does not express the metallo-proteinases (MMPs) -2 and -9, which may account for its indolent biological behavior. © 2012 Japanese Society of Neuropathology.