A Purely Endoscopic and Simultaneous Transsphenoidal and Transcranial Keyhole Approach for Giant Pituitary Adenoma Resection: A Technical Case Report

: A combined transsphenoidal-transcranial approach for the resection of pituitary adenomas has previously been reported. While this approach is useful for specific types of pituitary adenomas, it is an invasive technique. To reduce the invasiveness of this approach, we adopted the keyhole concept for pituitary adenoma resection. A 23-year-old man presented at a local hospital with a 6-month history of bilateral hemianopia. Magnetic resonance imaging revealed a large pituitary adenoma extending from the sella turcica toward the right frontal lobe. Endoscopic transsphenoidal surgery was planned at a local hospital; however, the operation was abandoned at the start of the resection because of the firm and fibrous nature of the tumor. The patient was subsequently referred to our hospital for additional surgery. The tumor was removed purely endoscopically via a transsphenoidal and transcranial route. Keyhole craniotomy, 3 cm in diameter, was performed, and a tubular retractor was used to achieve a wider surgical corridor; this enabled better visualization and dissection from the surrounding brain and provided enough room for the use of surgical instruments under endoscopic view. The tumor was successfully removed without complication. This is the first case report to describe the resection of a giant pituitary adenoma using a purely endoscopic and simultaneous transsphenoidal and transcranial keyhole approach.