ABSTRACT
Objective To investigate the value of MR on diagnosis of intracranial primary lymphoma in immunocompetent patients.Methods The MR features of 28 cases with pathology proved intracranial primary lymphoma were analyzed retrospectively.Conventional MRI scans,enhanced MRI scan were observed.Immunohistochemical staining were done and the results were compared with the MR imaging signs. Results Twenty-eight cases were all B-cell type Non-Hodgkin's lymphoma,16 cases were single lesion (57%)and 12 cases were multiple lesions (43%).The tumors mainly located in the deep white matter,7 cases in callus corpus and grew crossing the midline supratentorial.The lesions presented mass or node (20/28),11 cases showed massive edema.On T1WI,lesions were mostly hypo-or iso-intense to gray matter.On T2WI,tumors showed iso-or hyper-intense.All lesions presented hyper-or iso-to hyper-intense on diffusion weighted imaging(DWI).Most lesions show marked mass-like or nodular-like contrast enhancement on MR imaging,8 cases presented"incision sign",5 cases showed"fist sign"and 7 cases showed"butterfly-like".Immunohistochemical staining showed that GFAP(-) was 78.6% (22/28),as well as CD20 (+)96.4% (27/28),CD79α(+)67.9% (19/28),CD10(+)10.7% (3/28),Bcl-6 (+)75% (21/28),Mum1 (+)89.3% (25/28).Ki-67 was greater than or equal to 50% (22/28).Among the 28 patients,25 cases (89.3%) showed an"activated non-germinal center B-cell(non-GCB)"in origin and 3 cases(10.7%)were considered as a"GCB"subset.Conclusion The imaging features of marked mass-kike or nodular-like on MRI enhancement scan and hyper-or iso-to hyper-intense on DWI are helpful in the diagnosis and the differential diagnosis of intracranial primary lymphoma.