原发性脑内恶性淋巴瘤的CT、MRI诊断

目的 探讨原发性脑内恶性淋巴瘤的CT、MRI表现特征。资料与方法 回顾性分析11例经病理证实的原发性脑内恶性淋巴瘤的CT、MRI资料(其中4例同时进行CT、MRI扫描,1例仅有CT资料,6例仅有MRI资料),并与病理资料进行对照分析。结果 11例中10例为单发,1例多发,共有12个病灶,其中位于脑室旁深部白质的病灶4个,占33．3％,位于脑表面及灰白质交界区有7个,占58．3％,位于小脑部1个,占8．4％。原发性脑内恶性淋巴瘤的影像学形态多为类圆形肿块或结节,瘤周水肿及占位效应较轻。5例病变CT平扫表现为等或略高于脑组织密度影,无出血和钙化,注射对比剂后呈团块状或结节状均匀性强化;10例MR平扫中,T1WI上9个病灶呈等信号或略低信号,其余2个病灶呈低信号;在T2WI上,8个病灶呈等信号,3个呈略高信号,增强扫描显示病灶呈团块状或结节状均匀性明显强化。病理上肿瘤细胞均呈弥漫密集分布,瘤细胞大小较一致,胞质及水分少,核大,可见瘤细胞围绕血管呈袖套样浸润,未见明显的出血及坏死,亦未见钙化,网状纤维染色显示纤维结构较丰富,此种病理组织学特点决定了淋巴瘤具有一定的影像学特点。结论 原发性脑内恶性淋巴瘤的病理学基础决定其CT、MRI表现特征,结合其影像学表现和临床资料多可做出正确诊断。

CT and MRI Diagnosis of Primary Intracerebral Malignant Lymphoma

Objective To investigate CT and MRI features of primary intracerebral malignant lymphoma (PICML).Materials and Methods CT and MRI findings in 11 patients with pathologically-proved PICML were retrospectively analyzed. Both CT and MRI scanning were performed in 4 patients, while only CT scanning was performed in 1 patient and only MRI scanning in 6 patients. The findings were compared with pathologic results.Results Of 11 cases, single lesion was seen in 10 and multiple lesions in one. Of the total 12 lesions, 4 were located in para-ventricular deep white matter (33.3%), 7 at encephalic surface and white-gray matter junction (58.3%) and one in the cerebellum (8.4%). Usually, the lesion was presented as an oval mass or nodule with slight para-tumorous edema and space-occupying effect. On plain CT scans of 5 cases, the lesion presented as iso- or slight hyper-density shadow relative to gray matter without hemorrhage or calcification, and showed homogeneous mass-like or nodular enhancement after contrast injection. Of 11 lesions found on plain MRI in 10 cases, 9 presented as iso- or slight hypo-signal and 2 as hypo-signal on T 1WI, while 8 displayed as iso-signal and 3 as slight hyper-signal on T 2WI. Obvious homogeneous mass-like or nodular enhancement was seen on Gd-DTPA-enhanced MRI. Pathologically, the tumor cells were diffusely distributed and roughly same-sized with less cytoplasm and enlarged nucleus, infiltrating into the circumference of the vessels. The tumor was rich in fibers and showed no hemorrhage, necrosis or calcification. Conclusion PICML carries certain CT and MRI features, which are in accord with its corresponding pathologic characteristics. Correct diagnosis can be made in most cases when imaging findings are combined with clinical information.