成人幕上原始神经外胚层肿瘤的影像学表现及临床病理特点分析

CT and MRI findings and pathological characteristics of adult supratentorial primitive neuroectodermal tumors

目的探讨成人幕上原始神经外胚层肿瘤(supertentorial primitiv eneuroectodermal tumors,SPNET)的CT、MRI影像学表现及临床病理特点,以提高对本病的认识。方法回顾性分析12例经手术病理证实的成人SPNET的CT、MR影像特点及临床病理资料,并复习文献。结果 112例SPNET均位于幕上大脑半球脑实质内,均累及灰白质,位置较表浅;2肿瘤体积较大,平均直径约6.3 cm,直径大于5 cm者9例;3肿瘤占位效应明显,但瘤周水肿轻或无,3例瘤周未见水肿,7例瘤周轻度水肿,2例瘤周中度水肿;48例可见囊变坏死,4例为实性肿块,肿瘤实质部分CT平扫为稍高密度或等密度,MRI扫描T1WI呈等或稍低信号、T 2WI呈等或稍高信号,增强扫描明显强化;囊变坏死的范围相对较小,较大的囊变区域常位于肿瘤边缘;5病理学检查显示肿瘤为高度恶性小圆细胞性肿瘤,免疫组化示CD99(8/12)、胶质纤维酸性蛋白(8/12)、突触素(12/12)、神经元特异性烯醇化酶(6/12)阳性较多。结论成人SPNET罕见,影像学表现多样,但有一定特点,确诊有赖病理学及免疫组化检查。

Objective To investigate the imaging manifestations of CT and MRI and clinicopathological features of adult su- pratentorial primitive neuroectodermal tumors（SPNET） in order to improve the recognition of the disease. Methods The imaging mani- festations of CT and MRI and clinicopathological data of 12 patients with SPNET that was confirmed by operation were retrospectively analyzed. Related references were also reviewed. Results ①All the lesions were found in the supratentoriai cerebral hemisphere inclu- ding gray and white matters. The location was superficial. ②The tumors were large. The average diameter was about 6. 3 cm. There were 9 cases with tumor larger than 5 cm. ③The tumors mass effect was obvious with or without peritumoral edema. There were 3 cases with- out peritumoral edema,7 with light edema and 2 with moderate edema. ④ There were 8 cases with cystic necrosis and 4 cases with solid tumors. CT images showed that solid component of all lesions was slightly hyper density or equidensity. MRI T1WI presented an equisig- nal or slight low signal while MRI T2WI showed an equisignal or slightly hyper signal with obvious enhancement. The scope of cystic necrosis was relatively small and the lager cystic region always located in the edge of tumors. ⑤Histopathological examination showed that all the lesions were highly malignant small round cells. Immunohistochemical test demonstrated that there were more expressions of CD99（8/12） ,GFAP（8/12） ,Syn（12/12）and NSE（6/12）. Conclusion The adult SPNET is rare. The imaging manifestations are va- rying but there are certain characteristics. The definitive diagnosis should be decided by examinations of pathology and immunohisto- chemistry.