[A Case of Intradural Retroclival Chordoma]

A 67-year-old woman was referred to our department with a retroclival lesion including a cyst on MRI. MRI revealed a lesion appearing as an isointense region on a diffusion-weighted image(DWI). Gadolinium(Gd)-DTPA T1-WI showed heterogeneous enhancement of the lesion in the prepontine cistern. Computed tomography(CT)revealed an isodense lesion with no invasion into the clival bone. Based on a preoperative diagnosis of retroclival chordoma, extended trans-sphenoidal surgery(TSS)was performed by a direct endoscopic endonasal approach via the left nostril. We found a round dural defect with a diameter of 5 mm, through which the tumor was incarcerated. However, the tumor had no connection to the clival bone. The lesion was totally removed and histologically diagnosed as a chordoma. Furthermore, the clival bone included no tumor cells. Based on those radiological and histological findings, we diagnosed the lesion as an intradural retroclival chordoma. We should consider intradural retroclival chordoma as a candidate for the differential diagnosis of a retroclival lesion without clival bone invasion.