Imaging features of primary central nervous system lymphoma at presentationseries from a regional cancer centre

Results : Seventy lesions were found, with a mean diameter of 20 mm. The most frequent locations of PCNSL were the periventricular region in 18 patients (41.9%), followed by cerebral hemispheres in 10 (23.2%). Four patients (9.3%) had a lesion in the corpus callosum, 2 (4.6%) in basal ganglia bilaterally and 6 (13.9%) had diffuse white matter involvement. A dural-based metastatic lesion was evident in 1 patient (2.3%) and 2 (4.6%) had a lesion originating from the wall of the third ventricle. One patient presented with an epidural mass in the spinal canal at the level of the second lumbar vertebra. Edema was seen in 35 patients (81.4%), identified on T2-weighted images, and a mass effect was evident in 5 (14.2%). The lesions were hyperintense in 4 patients (9.3%) and hypointense in 9 (20.9%); the remainder (69.8%) had heterogeneous signal intensity. Conclusions : PCNSL has a varied initial diagnostic imaging presentation with periventricular location being most common. Radiologically, PCNSL can mimic a variety of benign and malignant processes. New diagnostic tools are required for differentiation, such as single-photon emission computed tomography (SPECT), MR spectroscopy, perfusion MRI and iron nanoparticle studies. These tools can help in the differential diagnosis of neoplastic phenomena with inflammatory conditions and should be further investigated in clinical trials.