Gomez-Brouchet A, Delisle M B, Cognard C, Bonafe A, Charlet J P, Deguine O, Fraysse B
Department of Pathology, Centre Hospitalier Universitaire, Toulouse, France.
Otol Neurotol. 2001 Jan;22(1):79-86. doi: 10.1097/00129492-200101000-00016.
The indication for surgery of vestibular schwannomas (VS) remains controversial and depends on several factors. The ability to predict their patterns of growth would allow better surgical planning. This growth may depend on tumoral proliferation but also depends on dystrophic changes.
The aim of this study was to evaluate the role of magnetic resonance imaging (MRI) in predicting the evolution of VS. For this purpose, the authors attempted (1) to compare the MRI appearance of VS with its histopathologic features, (2) to correlate the MRI appearance of VS and its histopathologic features with its size, and (3) to evaluate the index of proliferation (IP) of each VS.
Thirty VS were studied with MRI before surgery. The VS were measured and classified as homogeneous, heterogeneous, and cystic. After surgery, IP was evaluated with immunohistochemical study using MIB-1 monoclonal antibody, and compared with tumor size. Pathologic studies evaluated the prevalence of Antoni type A and type B tissue, the amount of fibrosis, and the presence of siderin-loaded macrophages, xanthomatous cells, and cysts.
The IP was low (0.2%-2.2%) and was not correlated with VS size. On MRI, 13 VS were homogeneous, 12 heterogeneous, and 5 cystic. The 13 homogeneous VS were smaller and were predominantly made of Antoni type A tissue. The 12 heterogeneous and 5 cystic VS were larger and were predominantly made of Antoni type B/mixed tissue. Heterogeneous and cystic VS showed significantly more hemosiderin deposits. There was a significant relation between the amount of hemosiderin deposits and the mean size of VS. Microscopic cysts were observed only in VS with cystic MRI appearance. Fibrosis was present in all tumors regardless of their size and MRI appearance.
A heterogeneous MRI aspect (correlated with larger mean size) not only is related to the ratio of type A to type B tissue but also is caused by other pathologic changes, mainly hemosiderin deposits and cystic formation. Increasing tumor size probably depends less on IP than on dystrophic changes (hemosiderin, cysts) and/or on the presence of type B tissue.
前庭神经鞘瘤（VS）的手术指征仍存在争议，且取决于多种因素。预测其生长模式的能力将有助于更好地进行手术规划。这种生长可能取决于肿瘤增殖，但也取决于营养不良性改变。
本研究的目的是评估磁共振成像（MRI）在预测VS演变中的作用。为此，作者试图（1）比较VS的MRI表现与其组织病理学特征，（2）将VS的MRI表现及其组织病理学特征与其大小相关联，以及（3）评估每个VS的增殖指数（IP）。
对30例VS患者在手术前进行MRI检查。测量VS并将其分类为均匀型、不均匀型和囊性。手术后，使用MIB-1单克隆抗体通过免疫组织化学研究评估IP，并与肿瘤大小进行比较。病理研究评估了Antoni A型和B型组织的患病率、纤维化程度以及含铁血黄素巨噬细胞、黄色瘤细胞和囊肿的存在情况。
IP较低（0.2%-2.2%），且与VS大小无关。在MRI上，13例VS为均匀型，12例为不均匀型，5例为囊性。13例均匀型VS较小，主要由Antoni A型组织构成。12例不均匀型和5例囊性VS较大，主要由Antoni B型/混合组织构成。不均匀型和囊性VS显示出明显更多的含铁血黄素沉积。含铁血黄素沉积量与VS的平均大小之间存在显著关系。仅在MRI表现为囊性的VS中观察到微小囊肿。无论肿瘤大小和MRI表现如何，所有肿瘤均存在纤维化。
MRI表现为不均匀型（与较大的平均大小相关）不仅与A型和B型组织的比例有关，还由其他病理变化引起，主要是含铁血黄素沉积和囊肿形成。肿瘤大小的增加可能更多地取决于营养不良性改变（含铁血黄素、囊肿）和/或B型组织的存在，而不是IP。
