Asari S, Maeshiro T, Tomita S, Kawauchi M, Yabuno N, Kinugasa K, Ohmoto T
Department of Neurological Surgery, Okayama University Medical School, Japan.
J Neurosurg. 1995 May;82(5):726-38. doi: 10.3171/jns.1995.82.5.0726.
Meningiomas arising from the falcotentorial junction are extremely rare. The authors describe the clinical features, neuroimaging studies, and results of surgical treatment of meningiomas of the falcotentorial junction and clarify the characteristics of this lesion based on a review of the literature and seven patients treated at their institution. The most common symptoms resulted from intracranial hypertension. Upward-gaze palsy appeared in only one patient. Computerized tomography (CT) showed no specific findings, but there was no evidence of edema around the tumor. Magnetic resonance (MR) imaging revealed a round, smooth-bordered mass with a peritumoral rim, without edema, and showing marked contrast enhancement. The multiplanar capability of MR imaging delineated the relationship between the tumor and adjacent structures better than did CT. Detailed knowledge of the vascular structures, especially evidence of occlusion of the galenic venous system and the development of collateral venous channels, is critical for successful surgery; stereoscopic cerebral angiography is necessary to achieve this aim. The seven patients described developed five types of collateral venous channels: through the basal vein of Rosenthal to the petrosal vein, through the veins on the medial surface of the parietal and occipital lobes to the superior sagittal sinus, through superficial anastomotic veins, through veins of the posterior fossa to the transverse or straight sinus, and through the falcian veins to the superior sagittal sinus. The first three types mainly developed after occlusion of the galenic system. The tumors were removed through the occipital transtentorial approach with a large window at the posterior part of the falx. A favorable prognosis for patients undergoing surgical treatment of falcotentorial junction meningiomas can be expected if detailed neuroimaging studies and microsurgical techniques are used.
起源于小脑幕切迹交界处的脑膜瘤极为罕见。作者描述了小脑幕切迹交界处脑膜瘤的临床特征、神经影像学检查及手术治疗结果，并通过文献回顾及在其机构治疗的7例患者，阐明了该病变的特点。最常见的症状是颅内高压所致。仅1例患者出现向上凝视麻痹。计算机断层扫描（CT）未显示特异性表现，但肿瘤周围无水肿迹象。磁共振（MR）成像显示一个边界光滑的圆形肿块，有瘤周边缘，无水肿，且有明显的对比增强。MR成像的多平面能力比CT更能清晰显示肿瘤与相邻结构的关系。详细了解血管结构，尤其是大脑大静脉系统闭塞的证据及侧支静脉通道的形成，对手术成功至关重要；立体脑血管造影是实现这一目标所必需的。所描述的7例患者形成了5种类型的侧支静脉通道：通过Rosenthal基底静脉至岩静脉，通过顶叶和枕叶内侧面的静脉至上矢状窦，通过浅表吻合静脉，通过后颅窝静脉至横窦或直窦，以及通过镰旁静脉至上矢状窦。前三种类型主要在大脑大静脉系统闭塞后形成。肿瘤通过枕下经小脑幕入路切除，在小脑镰后部开一个大窗口。如果采用详细的神经影像学检查和显微外科技术，小脑幕切迹交界处脑膜瘤患者手术治疗有望获得良好预后。
