表皮样囊肿非典型MRI表现

目的探讨非典型表皮样囊肿MRI表现。方法回顾性分析4例经手术病理证实的表皮样囊肿的MRI资料。结果例1肿瘤位于左前中颅凹底,信号不均,T1WI呈高及低信号,T2WI及FLAIR像均呈高信号,其内有细曲线样等信号,左侧大脑半球脑裂、脑沟内散在点条状高信号。例2肿瘤位于左颞极,T1WI、T2WI及FLAIR像均为高信号,脑室、脑裂、脑池及部分脑沟内见点状高信号,脂肪抑制像信号减低。例3肿瘤位于右中颅凹底,边界清晰,呈类圆形,信号不均,T1WI呈低信号,其内见弧条状高信号,T2WI为高信号,其内见弧条状低信号,FLAIR像信号稍低,其内见云絮状稍高信号。例4肿瘤位于脑干前方,边界清晰,形态欠规则,T1WI、T2WI及FLAIR像均为高信号,脂肪抑制像仍为高信号。结论表皮样囊肿可表现出多种不典型MRI征象,信号特点多样,且可破裂播散至脑室内形成脂-液平面及在蛛网膜下腔内见到点条状脂肪信号,硬膜外表皮样囊肿更不具特异性,认识这些征象对临床诊断及治疗都有重要意义。

The atypical MRI manifestations of epidemoid cyst

Objective To investigate the atypical MRI manifestations of epidemoid cyst. Method MRI images of 4 cases of epidemoid cyst proved by surgery and pathology were analyzed retrospectively. Result The tumor of case 1 was located in the bottom of the left anterior-middle cranial fossa,whose signal was not uniform,high and low signal on T1WI and high signal on T2WI and FLAIR with thin-thread equal signal,dot-strip high signal in the left schizencephaly and sulcus.Case 2 which was in the left temporal pole,showed high signal on T1WI,T2WI and FLAIR sequence,and there were spot high signal in cerebral ventricle,schizencephaly, cistern and some sul-cus, and the signal in the fat-suppression sequence decreased. The focus of case 3 with nearly round shape and clear boundary was located in the bottom of the right middle cranial fossa,manifested unequal signal intensity,low signal with circle-curved high signal on T1WI,high signal with circle-curved low signal on T2WI and little low signal with cloudy little high signal on FLAIR sequence. In case 4,the tumor with clear boundary and irregular form was in the front of brain stem,and the signal intensity was high on T1WI,T2WI,FLAIR image,and fat-suppression image. Conclusion Epidemoid cyst show many atypical MRI manifestations, the signal are diverse. The disease even shows disrupting into ventricle to form lipid-liquid boundary,and dot-strip high signal in subarachnoid space. The knowledge about these manifestations is important to clinical diagnosis and treatment of the tumor.