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目的探讨儿童颅内毛细胞型星形细胞瘤(PA)的影像学诊断及分析误诊原因。方法回顾性分析36例经手术病理证实为PA而术前误诊为其他肿瘤的病例,男性23例,女13例,分析其CT和MRI表现,总结误诊原因。结果36例PA中,14例位于小脑,7例位于鞍区,6例位于大脑,5例位于脑干,3例位于松果体区,1例多发病灶。其中5例(13.9%)见肿瘤内钙化,3例(8.3%)见肿瘤内出血,21例(58.3%)表现为各种不典型强化,2例(5.6%)出现脑脊液播散。11例的Cho/NAA平均值为2.53±0.94,其中9例Cho/NAA比值>2,4例可见Lac峰。本组35例(97.2%)DWI呈等、低信号。结论肿瘤内钙化、出血,不典型强化方式,软脑膜播散,多发病灶以及与恶性肿瘤相似的MRS表现是PA的误诊原因。DWI呈等或低信号,肿瘤边界清楚,无或轻度瘤周水肿则支持PA的诊断。
Objective To investigate the imaging diagnosis and misdiagnosis of intracranial pilocytic astrocytoma (PA) in children. Methods Retrospective analysis of 36 cases confirmed by surgery and pathology PA misdiagnosed as other tumors before surgery, 23 males and 13 females, CT and MRI findings were analyzed, and the causes of misdiagnosis were summarized. Results Among the 36 PA cases, 14 were located in the cerebellum, 7 in the saddle, 6 in the brain, 5 in the brainstem, 3 in the pineal region, and 1 in multiple lesions. Of these, 5 (13.9%) had in-tumor calcification, 3 (8.3%) had intra-tumor hemorrhage, 21 (58.3%) exhibited atypical enhancement and 2 (5.6%) had cerebrospinal fluid dissemination. The average Cho / NAA in 11 cases was 2.53 ± 0.94. Among 9 cases, Cho / NAA ratio> 2 cases showed Lac peak. The group of 35 patients (97.2%) DWI was equal, low signal. Conclusion In-tumor calcification, hemorrhage, atypical enhancement, leptomeningeal spread, multiple lesions and MRS manifestations similar to malignant tumors are the causes of PA misdiagnosis. DWI was equal or low signal, clear tumor border, no or mild peritumoral edema is to support the diagnosis of PA.