毛细胞黏液样型星形细胞瘤的临床病理学观察

目的探讨毛细胞黏液样型星形细胞瘤的临床病理学特点。方法观察3例毛细胞黏液样型星形细胞瘤的光镜形态,采用EnVision法免疫组织化学标记胶质纤维酸性蛋白（GFAP）、CD34、Ki-67,并结合文献复习分析其生物学行为。结果3例均为女性,年龄分别为9个月、10岁和19岁。1例发生于视交叉,2例发生于第三脑室（近鞍区部位）。镜下由双极性的梭形细胞组成,间质内含有大量的黏液。肿瘤内的血管明显增生,部分区域内瘤细胞显示以血管为中心性生长。3例切片内均未见到经典型毛细胞星形细胞瘤中的双相性形态,也未见Rosenthal纤维和嗜酸性颗粒小体。免疫标记显示,瘤细胞强阳性表达GFAP,瘤细胞增殖指数（Ki-67）〈1％。CD34标记显示清晰瘤内增生的血管。结论毛细胞黏液样型星形细胞瘤是毛细胞星形细胞瘤的一种独特亚型,在组织学上与毛细胞星形细胞瘤有不同之处,临床上较毛细胞星形细胞瘤更具有侵袭性。部分病例也可发生于儿童和青少年。GFAP标记有助于该瘤的诊断和鉴别诊断。

Pilomyxoid astrocytoma: a clinicopathologic study of three cases

Objective To study the clinicopathologic features of pilomyxoid astrocytoma (PmA). Methods The clinical and pathologic features in 3 cases of PmA were analyzed. Immunohistochemical study for glial fibrillary acidic protein (GFAP), CD34 and Ki-67 was performed on paraffin-embedded sections by standard EnVision method.Results All the 3 cases occurred in female patients at the age of 10 months, 10 years and 19 years respectively. Two cases were located in the third ventricle, while the remaining case was located at the optic pathway. Histologically, the tumor was composed of bipolar spindle cells setting in a strikingly mucinous background. There was a marked proliferation of vessels within the tumor. In some areas, the tumor cells exhibited an angiocentric growth pattern. The biphasic pattern noted in a classic pilocytic astrocytoma was not found in PmA. Rosenthal fibers and eosinophilic granular bodies were also not identified. Immunohistochemcal study showed that the tumor cells were diffusely positive for GFAP. The Ki-67 labeling index measured less than 1%. CD34 highlighted mainly the vascular networks. Conclusions PmA is a distinctive variant of pilocytic astrocytoma with subtle histologic differences. Compared with conventional pilocytic astrocytoma, PmA behaves more aggressively. Some cases tend to occur in older children and adolescents. Immunohistochemical study for GFAP is helpful in differential diagnosis.