磁場式ナビゲーション下に全摘し得た海綿静脈洞進展ACTH産生下垂体腺腫の1例

A Case of an Adrenocorticotropic Hormone-Producing Pituitary Adenoma Removed via Electromagnetic-Guided Neuroendoscopy

Ⅰ．はじめに

　下垂体腺腫の外科的治療において，再発予防の観点からは全摘出が最も望ましいが，海綿静脈洞進展がある場合，それが困難となるケースがしばしばある^4,20)．下垂体腺腫手術における術中支援として，ナビゲーションシステムは病変の位置，正常解剖を理解するために必要な手術支援モダリティーである²⁾．現在，脳神経外科領域で使用されているナビゲーションは，光学式と磁場式の2つの種類がある．磁場式は磁場フィールド内に存在するセンサー位置を持続的にトラッキングするため，光学式と比べ，自由な器具操作が求められる脳神経外科手術においてその有用性が報告されている⁸⁾．

　今回，われわれは右動眼神経麻痺で発症した海綿静脈洞進展adrenocorticotropic hormone（ACTH）産生下垂体腺腫に対して，磁場式ナビゲーション下に全摘出し得た1例を経験したので文献的考察を踏まえ報告する．

　The use of navigation systems is safe and reliable for neurological surgery. We performed endoscopic transsphenoidal surgery to totally resect an adrenocorticotropic hormone（ACTH）-producing pituitary adenoma associated with oculomotor nerve palsy.

　A 70-year-old woman developed right ptosis 4 months before admission. She developed anisocoria 2 months later and was referred to the department of neurology from clinic. Brain magnetic resonance imaging（MRI）showed an intrasellar tumor that partially invaded the right cavernous sinus, and she was then referred to our department. She exhibited a round face（“moon face”）and central obesity. Laboratory test results showed a high urinary cortisol level and high serum ACTH level, and neither the serum cortisol nor ACTH level was suppressed by a low-dose dexamethasone test. We performed transsphenoidal surgery using high-dimensional endoscopy under electromagnetic navigation. The tumor invading the cavernous sinus was visualized via endoscopy and confirmed on navigation using a flexible needle probe. Postoperative MRI showed total removal of the tumor, and the serum ACTH level recovered to the normal range. The patient's right oculomotor palsy resolved within 1 week postoperatively.

　In summary, electromagnetic navigation was useful for total resection of a pituitary tumor invading the cavernous sinus, contributing to normalization of the ACTH level and improvement in neurological symptoms.