女性，63岁，左侧额顶部肿胀6年余，并逐渐增大，无明显头痛，无外伤史，神经功能无明显异常。
CT增强扫描图像如下图所示：
In bone window (Fig. 1, 2): A left-sided frontoparietal intradiploic mass expanding the calvaria with segmental homogeneous thickening and sclerosis of diploe, inner and outer table. The inner table was irregular (Fig. 1).
骨窗（图1、2）示板障内肿块，局部颅骨膨胀、增厚，内外板及板障骨质硬化，内部表面不光整。
In soft tissue window (Fig. 3, 4): Cerebral parenchyma and meningeal spaces were normal.
软组织窗（图3、4）脑实质及脑膜腔未见明显异常。
发生在硬膜外的脑膜瘤又被称作：异位脑膜瘤、硬膜外脑膜瘤、颅骨脑膜瘤、颅外脑膜瘤或骨内脑膜瘤等。
Extradural meningiomas constitute 1 to 2% of all meningiomas [2]. Primary intraosseous meningiomas are a subtype of primary extradural meningiomas that arise in bone [3] and represent approximately two thirds of all extradural meningiomas [4]. The vast majority of primary intraosseous meningiomas involve the calvaria [5].
硬膜外脑膜瘤约占全部脑膜瘤的1%~2%。原发性骨内脑膜瘤是原发性硬膜外脑膜瘤的一种，发生于颅骨，约占全部硬膜外脑膜瘤的2/3。大部分原发性骨内脑膜瘤发生于颅顶。
Primary extradural meningiomas are classified as purely extracalvarial (type I), purely calvarial (typeII), or calvarial with extracalvarial extension (type III). According to the site of location of the tumour, Lang et al [4] further subdivided type II and III lesions into convexity (C) or skull base (B) forms. Because the cerebral parenchyma and meningeal spaces are normal, the case presented here is a type IIC meningioma.
原发性硬膜外脑膜瘤分为三型：单纯颅骨型（I型）、单纯颅外型（II型）、颅骨向颅外生长型（III型）。根据肿瘤的发病部位，Lang等人将II型和III型又进一步分为颅顶型和颅底型。此例病例中，脑实质和脑膜间隙显示正常，为IIC型脑膜瘤。
Primary intraosseous meningiomas occur with approximately the same frequency in each sex in the fifth decade [4].
原发性骨内脑膜瘤好发于50岁左右中年人，男女发病几率均等。
Clinically, as in our case, the majority of the primary intraosseous calvarial meningioma present as painless expansile masses with normal neurological findings [6]. These lesions may be asymptomatic and detected incidentally [7].
绝大部分的颅骨原发性骨内脑膜瘤表现为无痛性肿块，呈膨胀性生长，神经功能无明显异常。通常患者无明显症状，多为偶然间发现病变。
The radiographic appearance of intraosseous meningiomas depends largely on their location. They are typically either the osteoblastic or osteolytic subtype, although mixed versions have been reported. The majority of intraosseous meningiomas are osteoblastic subtype [8, 9]. CT with bone windows shows a focally thickened, hyperdense intradiploic lesion expanding the calvaria. The tumour is usually hyperdense on unenhanced CT and there is no enhancement in osteoblastic subtype after contrast administration. More rarely, primary intraosseous meningioma may present as an osteolytic skull lesion, typically cause thinning, expansion, and interruption of the inner and outer cortical layers of the skull. The lesions are similarly hyperdense on a nonenhanced CT and enhance homogeneously after contrast administration [8, 10]. MR imaging provides a better anatomic delineation in the evaluation of the soft tissue component and extradural extension of the lesion. But, MRI is less sensitive than CT for the detection of bone lesions. On MRI, the tumours are typically hypointense on T1 weighted images and hyperintense on T2-weighted images. Prominent homogeneous enhancement after Gadolinium administration is typical. Enhancement of the underlying dura may be noted. This dural enhancement could be secondary to dural irritation or tumour invasion [11].
骨内脑膜瘤的影像学表现与病灶的位置有很大关系，一般可分为溶骨性和成骨型，也有少量报道为混合型。
大部分骨内脑膜瘤为成骨型，CT骨窗可表现为颅骨膨胀，板障增厚、密度增高。平扫时，病灶呈高密度，增强后成骨型病灶一般无明显强化。很少部分骨内脑膜瘤表现为溶骨型，CT表现为颅骨内外板膨胀、变薄，骨皮质可不连续。平扫时病灶呈高密度，增强后可见均匀强化。
MRI评价肿瘤的软组织成分及硬膜外间隙受侵方面有一定优势，但对骨组织的显示不如CT。MRI上，病灶T1WI通常为低信号，T2WI为高信号，增强扫描，病灶一般呈明显均匀强化。有时可见临近硬脑膜强化，这种表现通常与脑膜刺激或肿瘤侵犯有关。
Our patient underwent an elective biopsy procedure of the parietal bone by the neurosurgery service. The histopathology results indicated an intraosseous meningioma. There was no nuclear pleomorphism, necrosis, or high mitotic activity indicative of malignancy. It had a grade I according to WHO grading.
该患者行顶骨活检，病理结果为骨内脑膜瘤，细胞核无明显异型性，无坏死或提示恶性的高度分裂，WHO分级为I级。
Complete resection with reconstruction is the only potentially curative treatment. Recurrence rates for all locations are estimated to be between 10% to 23% [12, 13].
手术全切加颅骨重建是唯一的治疗方法。术后复发的几率月10%~23%