CT AND MR-IMAGING IN PRIMARY CEREBRAL NON-HODGKINS-LYMPHOMA

Purpose: To determine the morphological appearance and topographical d istribution of primary cerebral non-Hodgkin's lymphoma (NHL). Material and Methods: CT and MR examinations of 68 patients with primary cereb ral NHL were analyzed. The NHLs were classified by the Kiel classifica tion and immunohistological data, as centroblastic (25), immunoblastic (24), lymphoblastic (5), Burkitt (1), non-subclassifiable type B (11) , and T cell lymphoma (2). Results: Centroblastic lymphomas tended to predominate in the parietal lobe (56.5%) and the corpus callosum (59.1 %) while immunoblastic lymphomas were mainly distributed in the fronta l lobe (52.8%). About 2/3 of all NHLs showed a multifocal occurrence. Important for differential diagnosis, ventricular involvement was prov ed in 83.3% of these cases. In the remaining 26 patients with a solita ry lymphoma, a periventricular location could be detected in only 8 ca ses. Central necroses were frequent in HIV-positive patients (7/11, 63 .6%) but rare in the HIV-negative patients (9/57, 15.8%). On T2-weight ed SE MR images, 8/11 centroblastic lymphomas gave a signal that was i sointense with, or lower than, that of the contralateral white matter, while 8/10 immunoblastic lymphomas gave a higher signal. Conclusion: The radiological finding of multifocal brain lesions with ventricular involvement is relatively specific for primary cerebral NHL. However, subclassification on the basis of the CT or MR imaging results is not yet possible.