脑膜瘤

Meningioma

根据WHO的中枢神经系统肿瘤分类 ,脑膜瘤分为四类 :①脑膜瘤。②脑膜间质非脑膜上皮肿瘤。③原发性黑素细胞病变。④组织来源不明的血管母细胞瘤。脑膜瘤是一组分为15个亚型和3个恶性级别的杂类肿瘤 ,在脑膜肿瘤中最为多见。本文复习它们的影像学 ,介绍侵袭性脑膜瘤的概念和影像学表现。已经肯定 ,大多数骨质增生是由肿瘤直接浸润所致 ,对此情况应考虑侵袭性脑膜瘤的诊断。单个脑膜瘤可能为硬脑膜上范围相对较大的肿瘤野中生长突出而能见到。基于这个概念 ,复发性脑膜瘤可分为两类 :真性或局部性复发 ;假性或区域性的复发。非典型性和间变性脑膜瘤的影像学诊断是一个尚未解决的问题。本文对它们的CT和MRI的恶性征象及其可靠性进行探讨 ,本文叙述了囊性脑膜瘤和无症状性脑膜瘤的影像学 ,并对MRI所见脑膜尾征的意义进行探讨。

According to the WHO classification of tumors of the nervous system, tumors of the meninges are classified into four classes: meningioma, mesenchymal, non-meningotheial tumors, primary melancytic lesions and tumors of uncertain histogenesis that is hemangioblastoma. Most of them are meningiomas and they are considered to be a heterogeneous group of tumors that is categorized into 15 subtypes with three grades of malignancy. Imaging of these tumors is reviewed in this article. The concept and imaging of the aggressive meningiomas are introduced. It has been ascertained that most of hyperostosis in meningiomas is a result of direct tumor invasion, therefore, the diagnosis of aggressive meningioma should be considered in this situation. A single meningioma may represent only the visible predominant growth in the midst of a relatively wide neoplastic field in the dura matter, with this concept in mind the recurrent meningiomas can be classified into two categories: true or local recurrence and false or regional recurrence. The imaging diagnosis of atypical and anaplastic meningiomas is still an unsolved problem, and the signs of malignancy in CT and MRI and their reliabilities have been discussed. The imaging of cystic meningiomas and asymptomatic meningiomas, and the significance of dural tail showed in MRI are also addressed.