多形性黄色星形细胞瘤的CT、MRI表现及误诊分析

CT and MRI Features and Misdiagnostic Analysis of Pleomorphic Xanthoastrocytoma

目的探讨多形性黄色星形细胞瘤（PXA）的CT、MRI特征,以提高其术前诊断率。方法回顾性分析13例经手术病理证实为PXA患者的CT、MRI表现,并结合文献分析其误诊原因。结果 13例PXA患者中,发病年龄范围为7-56岁,平均（33.4±18.2）岁,女5例,男8例。病变位于幕上脑实质12例,延髓1例;12例为单发病灶,1例多发病灶,多发病灶位于左侧丘脑及右侧基底节区。大囊伴结节型5例（38.4%）,实质型3例（23.1%）,囊实性混合型5例（38.4%）。肿块实性部分T1WI呈等或稍低信号,T2WI呈等或稍高信号,囊性部分T1WI信号略高于脑脊液;3例行CT扫描,病灶均为囊实性,实性部分密度稍高,内可见结节状、小斑片状钙化灶。增强扫描大多肿块显著强化,其中1例轻度强化,仅2例可见病变接触的软脑膜强化。结论 PXA的MRI与CT表现具有一定特征性,综合分析有助于减少误诊,提高其术前诊断准确率。

Objective To investigate the CT and MRI features of pleomorphic xanthoastrocytoma（ PXA）,and improve the diagnostic accuracy. Methods The CT、MRI features and the causes of misdiagnoses were retrospectively analyzed in13 cases of PXA proved by operation and pathology. Results There were 8 males and 5 females. The patient＇s age ranged from 7 ~ 56 years old,with average age of（ 33. 4 ± 18. 2） y. 12 cases were supratentorial tumor,and 1 case located in the medulla oblongata. Of all the patients,only 1 case had multiple lesions. There were 5 cases which appeared as a cystic lesion with nodule,5 cases presented as cystic-solid lesion and 3 cases appeared as solid type. Cyst fluid showed slight hyperintensity in some cases on T1WI. Solid components showed isointensity or mild hypointensity on T1WI,and isointense or mildly hyperintense on T2WI,significant enhancement with contrast was seen in 12 cases,and slight enhancement with contrast in 1 case. Marked adjacent leptomeningeal enhancement could be seen in 2 cases. CT scanning was conducted in 3 cases and all 3 lesions were solid-cystic,with calcification in solid components. Conclusion There are some rather characteristic features of CT and MRI in PXA,which are very helpful to improve accuracy of diagnosis.