MRI Diagnosis of Primary Central Nervous System Lymphomas and Pathological Features

Purpose To evaluate MRI manifestations of PCNSL in immunocompetent patients,so as to improve MRI diagnostic accuracy of PCNSL.Materials and Methods The MRI and pathological findings in 23 patients with confirmed PCNSL were retrospectively analyzed.Results 41 lesions were identified in 23 patients,16(69.6%)patients with solitary tumor focus and the other 7(30.4%)presenting a multifocal form up to 25 lesions.39 of 41 lesions located at supratentorial brain,the other two at infratentorial brain.The most frequent locations were the cerebral hemispheres,the corpus callosum and periventricular white matter.78.1%(32/41)lesions with isointense or hypointense on T1-weighted images and isointense or slightly hypointense on T2-weighted images were detected.All lesions showed no blood flow.70.7%(29/41)lesions were found with obvious homogenous enhancement,typical with incision sign and angular sign,especially for those lesions adjacent to the subarachnoid space.9.6%(4/41)lesions showed microcystic foci and ring sign after gadolinium enjection.All the 23 patients were pathologically diagnosed as B cell lymphoma,one of whom as Burkitt lymphoma,the other 22 as diffuse larger B-cell lymphoma.Under light microscope,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 Conventional MRI plays an important role in making accurate diagnosis in most patients with PCNSL.The MRI features of PCNSL base on its pathological characteristics and final diagnosis of the entity depends on pathology.