脳動脈瘤を合併した下垂体腺腫の特徴および治療方針に関する検討

A Clinical Feature and Therapeutic Strategy in Pituitary Adenomas Associated with Intracranial Aneurysms

Ⅰ．はじめに

　下垂体腺腫に対する脳動脈瘤の合併頻度は5.4～7.4％^8,13)といわれており，その頻度は健常人の未破裂脳動脈瘤の保有率と比べ，同等もしくは高率である．一方，経蝶形骨洞手術は低侵襲な手術法として下垂体腺腫を含めたトルコ鞍病変の標準的手術法として確立されているが，術野や使用器具が制限されるため，脳動脈瘤のクリッピング処置は困難である．よってトルコ鞍近傍の脳動脈瘤の有無を術前に確認することは重要であり，両者が合併した際に治療をどのような方法，順序で行うかを決定しなければならない．今回，自施設で経験した脳動脈瘤を伴った下垂体腺腫における特徴や治療内容，問題点について検討した．

　We studied the clinical feature and treatment strategy of pituitary adenomas associated with intracranial aneurysms. Among 102 pituitary adenoma patients (mean age: 54.8 years old) who received MR angiography and/or 3D-CT angiography,seven patients (6.9%) had intracranial aneurysms. The association of an aneurysm was more common in large size adenomas (p＜0.05). According to the location of the aneurysms,five patients had these in the paraclinoid portion or cavernous portion of the internal carotid artery. Using MR images,we classified the aneurysms associated with pituitary adenomas as non-adjacent,adjacent,and intra-adenoma types. In non-adjacent types,an aneurysm is located apart from the adenoma,and has less chance of exposure during transsphenoidal surgery. In adjacent types,an aneurysm is located adjacent to the adenoma,and could be exposed during transsphenoidal surgery. In intra-adenoma types,an aneurysm is encased in the adenoma. In non-adjacent type aneurysms,a resection of the pituitary adenoma can be carried out before aneurysm treatment due to the low risk of rupture during surgery. In adjacent types,a tumor resection can precede aneurysm treatment in cases of low rupture risk aneurysms and untreatable aneurysms. In intra-adenoma types,adenoma resection should come after treatment of the aneurysms. Neurosurgeons should be careful about not only the presence of aneurysms in preoperative images during transsphenoidal surgery planning,but also their locations and proximity to adenomas. Such information may be crucial in deciding the order of treatment.