Presentation
Visual symptoms
Patient Data
A right occipital lesion is gyral in morphology with a relatively low T1 signal, intermediate T2 signal (some areas are quite low, as low as the cortex, while other areas are somewhat brighter) and vivid fairly homogeneous contrast enhancement. It demonstrates low ADC values and strikingly high signal on DWI. It is surrounded by vasogenic edema, and the combination exerts a substantial mass effect with midline shift. A few small foci of blood product are also seen centrally within the mass.
Conclusion:
The diffusion characteristics are those of a very highly cellular tumor. The enhancement and gyral expansion strongly favor lymphoma.
Case Discussion
The patient went on to have a biopsy.
Histology
Sections show a diffuse confluent population of large atypical lymphocytes involving brain tissue. The tumor cells show strong diffuse expression for CD20, PAX5, MUM1, BCL6 and BCL2, with Ki-67 proliferative rate of 90%. There is a weak expression for CD5. Immunohistochemistry for CMYC is 80% (positive). The tumor cells are negative for CD10, CyclinD1, CD30, and EBER-ISH. Additional markers performed show the tumor cells to be negative for Sox11 and CD23.
Final diagnosis:
Primary diffuse large B cell lymphoma of the central nervous system (ABC subtype, co-expressor positive), EBV negative.
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