摘要目的 探讨毛细胞型星形细胞瘤(PA)的临床表现、病理特征、诊断、鉴别诊断及预后.方法 应用光镜、电镜及免疫组织化学EnVision法染色对68例PA进行观察分析,免疫组织化学染色抗体包括胶质纤维酸性蛋白(GFAP>、Ki-67和上皮细胞膜抗原(EMA).获得51例随访资料.结果 患者年龄3-66岁,平均年龄20.1岁,男35例,女33例.术前病程3 d至14年,平均371 d.影像学检查有囊性变者41例,增强后有强化者43例.发病部位以小脑最多见,为33例(48.5%).肿瘤全切除者35例,部分切除者31例,不详者2例.随访51例,其中生存44例,复发7例,死亡7例.生存者中,生存2个月至10年4个月,平均生存48.1个月.5年及10年生存率均为89%.组织学特征为:组织呈双相结构,由致密区梭形细胞伴Rosenthal纤维和疏松区多极细胞伴微囊及嗜酸性颗粒小体组成.部分病例出现细胞核异型性及偶见核分裂象,17例有肿瘤沿蛛网膜下腔侵犯.1例间变型PA.GFAP全部病例瘤细胞呈弥漫阳性表达,Ki-67除1例间变型PA为10%外,均表达较低.蛛网膜下腔侵犯处网状纤维染色多为阳性,EMA阴性.结论 PA属WHO I级星形细胞瘤,肿瘤全切除后无需放疗,一般预后良好.肿瘤沿蛛网膜下腔侵犯是PA的主要特点,加上部分病例瘤细胞核异形深染,常因此误诊为较高级别的星形细胞瘤.肿瘤部分切除者复发率较高.肿瘤位于脑干部位者及间变型PA预后较差.

abstractsObjective To study clinicopathologic features, treatment and prognosis of pilocytic astrocytoma (PA). Methods Histopathological, ultrastructural, immunohistochemical(EnVision method) and clinical features of 68 cases of PA were studied by microscopic investigation with correlation of clinical follow-up information when available. Results Thirty-five male patients and 33 female patients were studied The patient's age ranged from 3 to 66 years (mean=20.1 years). The mean time from symptom onset to surgery was 371 days (range,3 days to 14 years). Cystic degeneration was noted in 41 cases (60.3%), and enhancement of the tumor was noted in 43 cases (87.8%). On postcontrast imaging examination there were 33 cases involving the cerebellum (48.5%). Total tumor excision was performed in 35 patients, subtotal tumor excision was performed in 31 patients, and the procedures of other 2 patients were not clear. Among 51 patients with follow-up information, 44 were alive, 7 had recurrent tumor, and 7 died The post-operative survival ranged from 2 months to 124 months (mean survival=48.1 months). Five years and ten years survival rates were 89%, respectively. Tumors with classic histopathology demonstrated biphasic pattern of growth, consisting of compact elongated bipolar astrocytes associated with rosenthal fibers, and less cellular areas of multipolar cells with granular bodies and microcyst. Some cases showed atypia of nuclei, and occasional mitoses. Involvement of subarachnoid space was seen in 17 cases. One case had anaplastic features. All cases showed diffuse positive staining for GFAP and low expression for Ki-67, except 1 anaplastic tumor with 10% Ki-67 indices. Tumors with snharachnoid space involvement showed positive reticular fiber staining and negative EMA staining. Conclusions PA is a benign, WHO grade I tumor with favorable prognosis, and does not require radiotherapy after total resection. The tumor can be mistaken as higher-grade astrocytoma when involving the subarachnoid space, and with cytological atypia, leading to unnecessary radiotherapy after surgery. Recurrence rate is increased when only partial resection is achieved.The outcome for pafients with brainstem tumor or anaplastic PA is poor.