原发中枢神经系统淋巴瘤的MRI特点及其在脑组织活检中的应用

The MRI features of central nervous system lymphoma (PCNSL) and its implications in the biopsy.

目的探讨原发性中枢神经系统淋巴瘤(primary central nervous system lymphoma,PCNSL)的MRI成像病灶部位、大小、数目以及强化的特点。方法回顾分析2000年1月至2008年12月期间在中山大学附属肿瘤医院和附属第一医院住院,经病理证实的35例PCNSL患者的MRI表现。记录MRI上病灶的部位、大小、数目、强化特点、瘤周水肿大小、胼胝体有无受累等表现。结果35例患者共检出51个病灶,其中26例患者为单发,9例患者为多发。病灶从1个到5个,最多见的部位是大脑半球(52.9%),其次依次为基底节-丘脑区域(17.7%),所有病灶均表现有强化,但强化的程度有所不同,均匀强化的病灶有34个,不均匀强化的病灶有17个。瘤周水肿1级14个,2级31个,3级6个。35例患者中6例表现有胼胝体受累及。35例中有9例是经立体定向活检病理诊断,取材部位均为强化处或病灶边缘。结论PCNSL多数位于大脑半球,有占位效应,MRI成像强化明显,直径多大于20mm,侵犯胼胝体的病灶体积更大。MRI成像病灶强化明显或者病灶的边缘部位是立体定向脑活检的最佳部位。

Objective To characterize the MRI findings of primary central nervous system lymphoma （PCNSL） in immunocompetent patients. Methods The MRI brain imaging of Patients with pathological proved PCNSL were analyzed retrospectively. From Jan 2000 to Dee 2008, 35 patients were admitted into the cancer center and the first affiliated hospital of Sun Yat-sen University. Locations, sizes, numbers, enhancement characteristics of lesions, edema around the tumor and involvement of the corpus callosum on MRI were recorded and analyzed. Results Fifty-one lesions were found in 35 patients. The number of lesions ranged from 1 （ n = 26） to 5 （ n = 9） with a mean of 1.7. The most frequent locations were the cerebral hemispheres （ 27/51,52.9 % ）, basal ganglia-thalamus （9/51,17.7% ） and corpus eallosum （ 8/51,15.7 % ）. Contrast enhancement was found in all patients. Among them, 34 lesions exhibited homogeneous enhancement pattern and 17 lesions had inhomogeneous enhancement pattern. First, second and third levels of peritumoral edema were found in 14, 31 and 6 lesions, respectively. Nine patients were diagnosed by stereotaxis biopsy at contrast enhanced lesion site or the margin of the tumor. Conclusions The cerebral hemisphere is the commonest location of PCNSL. MRI features of PCNSL are mass, contrast-enhancing lesions with a diameter of at least 20 ram. The margin of lesion or the location with greatest contrast-enhancement would be the best site for biopsy.