腹膜后良性神经鞘瘤的影像学特征

Imaging Features of Benign Retroperitoneal Neurolemmoma

目的分析腹膜后良性神经鞘瘤的CT和MRI表现,总结其影像学特征。资料与方法经手术病理证实的27例腹膜后良性神经鞘瘤患者中,21例行多层螺旋CT检查,9例行MRI检查。观察CT、MRI平扫和增强时肿瘤的特征性改变。结果 27例腹膜后良性神经鞘瘤边缘规则光整,直径多在5～10cm之间,CT平扫肿瘤呈实性或囊实性。CT增强后动脉期轻至中度强化10例,主要呈云絮状、索条状强化;动脉期9例可见纤细血管显影。门脉期及延迟扫描轻度渐进性强化13例。MRI平扫呈不均匀长T1长T2影,DWI呈高信号,4例可见靶征改变,增强后门脉期及延迟呈渐进性强化。无一例发生淋巴结转移。结论腹膜后良性神经鞘瘤影像学表现具有一定特异性,CT结合MRI检查及多期增强扫描对其诊断有一定价值。

Purpose To discuss the CT and MRI findings of benign retroperitoneal neurolemmoma, and to summarize its imaging features. Materials and Methods Twenty seven cases of benign retroperitoneal neurolemmoma proved by surgery and pathology were admitted in this study. Among these cases, 21 cases underwent multi-slice CT （MSCT） and 9 cases underwent MRI, respectively. Pre- and post- contrast CT and MRI features of the tumor were obtained. Results All the 27 cases had well-defined benign retroperitoneal neurolemmoma. The diameter of tumors was from 5 cm to 10 cm. The tumors were solid or solid with cystic change on plain CT images. Enhanced CT demonstrated mild to moderate heterogeneous enhancement of the tumor in 10 cases, which showed flocculent or streaky enhancement. Tenuis vessels could be visualized in 9 cases. 13 lesions presented slight inhomogeneous delayed enhancement. Tumors showed heterogeneous low signal intensity on TIWI and high intensity on T2WI, and heterogeneous high signal on DWI. All the patients who underwent MRI enhanced scan presented slight or moderate inhomogeneous delayed enhancement in portal vein phase. 4 cases showed typical target sign. There was no lymph node metastasis. Conclusion Benign retroperitoneal neurolemmoma has characteristic CT or MRI features. CT and MRI examinations combined with multiple-phases enhancement will be helpful for the diagnosis.