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.