【罕少见】椎管内硬膜外脊膜瘤
病史：女，28岁，双手、大腿麻木伴乏力，逐渐加重8个月。
行MR平扫+增强扫描
影像表现：
MR：颈椎管内硬膜外异常信号灶，矢状呈梭形，轴位呈新月形，T2WI、T1WI均呈等信号，增强扫描显著均匀强化，内部信号均匀，并可见相邻硬脊膜增厚强化。
鉴别诊断：
脊膜瘤
海绵状血管瘤
血管脂肪瘤
转移瘤
淋巴瘤
术中所见：见椎管内有暗红色质软肉芽样肿瘤组织明显压迫脊髓，与黄韧带有部分粘连，与硬膜有浸润生长。
术后病理：（椎管内硬膜外）脊膜瘤。
椎管内硬膜外脊膜瘤
Spinal Epidural Meningioma
脊膜瘤起源于蛛网膜内皮细胞或硬脊膜的纤维细胞，是一种良性肿瘤。病变部位绝大多数位于髓外硬膜下，与硬膜关系密切，可见宽基底征。主要见于40～70岁的女性。
发生在硬膜外的脊膜瘤仅占所有脊膜瘤的3.5%-7.0%，更多见于儿童或青年而非成人。部分肿瘤可跨硬脊膜生长。
脊膜瘤的信号特点与脑膜瘤较一致，T2WI多呈等信号，亦可呈较高信号，T1WI呈等信号，增强扫描明显强化，信号较均匀。
看一例英文个案报道
History：A previously healthy 13-year-old girl presented with gradual onset of weakness in both legs and bowel and bladder incontinence.
(a) T1-weighted image shows the posterior epidural mass (arrow) has signal intensity similar to that of the spinal cord. The subarachnoid space is obliterated at the level of the mass, and the spinal cord is compressed. Note the normal shape and signal intensity of the vertebrae.
(b) T2-weighted image shows the mass has mixed signal intensity, with dura mater seen as a dark line (arrow) separating the extradural mass from the intradural structures. High signal intensity within the compressed spinal cord probably represents edema secondary to compression.
Contrast material– enhanced (a) sagittal and (b) transverse T1-weighted fast spin-echo MR images of the dorsal spine obtained with frequency-selective fat saturation depict strong and homogeneous contrast enhancement of the posterior epidural mass (arrow). In b, note complete filling of the posterior epidural space and lack of extension through the intervertebral foramina to the paravertebral space.
In summary, one should make the most likely diagnosis of spinal posterior epidural meningioma in this patient on the basis of the intermediate signal intensity seen on the T2-weighted image, the pattern of homogeneous enhancement, and the patient’s lack of blood disease and fever. Lack of foraminal extension and a paravertebral component make diagnosis of meningioma more likely than diagnosis of the other neurogenic tumors, such as schwannoma or neuroblastoma.