Endoscopic transsphenoidal resection of a large chordoma in the posterior fossa. Case report.

The authors report their encouraging experience using an endoscopic technique for transsphenoidal surgery in a patient with a large chordoma in the posterior fossa. The patient was a 40-year-old man with a 2-year history of progressive ataxia, a memory disorder, and emotional instability. A magnetic resonance (MR) image of the brain revealed a midline posterior fossa mass measuring 4 cm in diameter located between the clivus and the brainstem. The basilar artery and its bifurcation were encased by the tumor, which also distorted the brainstem. The patient had been treated at another hospital for obstructive hydrocephalus with a ventriculoperitoneal shunt and he received fractionated external-beam radiation treatment, although no histological diagnosis was ever made. The authors achieved a subtotal resection of the tumor through the patient's nostril using an endoscopic transsphenoidal technique. The portion of the tumor located behind the basilar artery was not resected to protect the brainstem perforating arteries. The patient showed dramatic improvement of his symptoms postoperatively. Residual tumor located behind the basilar artery was treated by stereotactic gamma knife surgery. This is the first reported case of a large posterior fossa chordoma treated by an endoscopic transsphenoidal technique.