多形性黄色星形细胞瘤影像学表现与病理学分析

Imaging findings and pathological analysis of pleomorphic xanthoastrocytoma

目的探讨多形性黄色星形细胞瘤(PXA)的影像学及病理学表现。方法回顾性分析2003-2011年间共12例经手术病理证实的PXA病人组织病理学、免疫组织化学和影像学资料。12例病人均行MRI平扫及增强检查,其中5例行CT平扫,2例行CT平扫和增强扫描。结果 12例病人病理组织学均可见不同程度囊变,瘤细胞呈明显多形性,肿瘤中有淋巴组织浸润,少有坏死,核分裂少或无。其中10例表达CD34。12例病人肿瘤均为单发,位于幕上。MRI平扫时实性部分T1WI呈等信号或稍低信号,T2WI为等信号或稍高信号;囊性部分T1WI呈低信号,T2WI呈高信号。MR增强扫描时肿瘤实性部分和壁结节明显强化。5例病人进行CT平扫,3例表现为低密度囊性病变伴等密度结节,2例呈低密度囊性病变,未见明显结节影;增强扫描可见明显的强化结节。结论 PXA具有一定的影像和病理学特征,综合对比分析可以确定诊断。

Objective To study the imaging and pathological findings of pleomorphic xanthoastrocytoma （PXA）. Methods Pathological, immunohistochemical, and imaging features were analyzed in 12 PXA cases confirmed by operation and pathology during 2003-2011. Twelve cases were examined with MRI and enhanced MRI. Five cases were examined with plain CT and 2 cases examined with plain and enhanced CT. Results In the pathological analysis, all cases showed cystic degeneration in varied degrees. Neoplastic cells were characterized by pleomorphism with tumor infiltrating lymphocytes. Scarce necrosis, and no or rare mitoses were identified. Neoplastic cells were strongly positive for CD34 in 10 cases. Twelve cases were located in supra-tentorial as a solitary lesion. The parenchymas of the tumors showed equal signal intensity or slightly low signal intensity on TIWI, and equal signal intensity or slightly high signal intensity on T2WI. The cyst of the tumors showed low signal intensity on TIWI, and high signal intensity on T2WI. The parenchymas of the tumors or the nodules were enhanced obviously. Among the five cases with plain CT, three cases appeared as cystic lesion with isodense nodule, and two cases appeared as cystic lesion without significant nodule. The nodules were obviously enhanced on enhanced CT. Conclusions PXA is a rare type of neuroepithelial tumors. Some imaging and pathological features are very helpful in making diagnosis.