颅内肿瘤样脱髓鞘病病理分期特点

Analysis of pathological characteristics of acute and chronic cerebral tumefactive demyeUnating lesions

目的总结经病理证实的58例颅内肿瘤样脱髓鞘病（TDL）发病不同时期的临床、影像及病理特点以减少误诊率。方法收集2005-2013年在海军总医院就诊，并经病理证实的58例TDL的临床、影像及病理资料进行回顾性分析，病理切片采用苏木精伊红染色（HE）、髓鞘染色[神经髓鞘固蓝染色法（LFB）、过碘酸．雪夫染色（PAS）或髓磷脂碱性蛋白（MBP）的免疫组织化学染色]和吞噬细胞特异抗体染色（KiMlP或CD68免疫组织化学染色）以及轴索染色[神经微丝蛋白（NF）免疫组化染色]，综合对TDL病灶组织进行病理观察。结果58例病例中男3l例，女27例，发病年龄6-56（36±13）岁。急性期21例（36％），亚急性期27例（46．5％），慢性期10例（17．5％）。2例患者为2次活检证实（3．4％）。急性期病理特点为大量神经髓鞘脱失而轴索相对保留，炎细胞（以吞噬细胞为主）大量浸润，反应性星形胶质细胞增多；慢性活动期病灶病理特点为相对的轴索保留，病灶与周围组织界限清楚。吞噬了髓鞘的吞噬细胞主要集中在病灶边缘，其细胞数较急性期减少，且处于非活动期，纤维型星形胶质细胞增多。结论TDL为特殊类型的脱髓鞘病，虽影像上貌似肿瘤，但其病灶多为双侧且彼此孤立，急性期与慢性期病理特点改变有差异。其病理演变特点对TDL早期诊断与鉴别诊断的临床价值显著，有助于与脑肿瘤或中枢神经系统血管炎相鉴别。

Objective To summarize the clinical features, neuroimaging findings and pathological characteristics of pathologically confirmed tumefactive demyelinating lesions （TDL）. Methods The clinical features, neureimaging findings and pathological characteristics were retrospectively collected and analyzed for 58 patients with pathologically confirmed TDLs. For pathological studies, a combination of hematoxylin and eosin staining, myelin staining （ Luxol fast blue/periodic acid-Schiff or immunohistochemistry for myelin basic protein）, macrophage-specific marker （immunohistochemistry for KiM1P or CD68） and staining for axons （Bielschowski silver impregnation or immunohistochemistry for neurofilament protein ） were employed. Results The mean age of onset was 6 - 56 （36± 13） years. The onsets were acute （ n = 21, 36% ）, subacute （n =27, 46. 5% ） and chronic （n = 10, 17.5% ）. The diagnoses of TDL were confirmed by repeat biopsy and pathological examinations （n = 2, 3.4% ）. In acute phase, the plaques of lesions were characterized by massive demyelination with relatively axonal preservation associated with prominent reactive astrecytosis and profound infiltrates of macrephages. In plaques of chronic lesions, demyelinated lesions with relative axonal preservation and sharply defined margins were major findings. And myelin-laden macrophages accumulated at the edges of plaques and stayed relatively inactive with densely gliotic center and processbearing astrocytosis. Conclusion TDL is a distinct entity of demyelinating disease. Even though it is often misdiagnosed as neoplasm in brain, bilateral brain involvements and multiple lesions are more common in TDL. The pathological features of TDL are important for the early diagnosis of this disease and helpful for differentiating with brain tumors and central nervous system vasculitis.