Studies of primary central nervous system lymphoma with fluorine-18-fluorodeoxyglucose positron emission tomography.

Primary CNS lymphoma is a rare and highly malignant primary brain tumor. Ten patients with biopsy-proven primary CNS lymphoma were studied with 18F-2-fluoro-2-deoxy-D-glucose (FDG) and positron emission tomography (PET) to demonstrate the findings in patients with this tumor. The accumulation of FDG in primary CNS lymphoma is similar to that seen in anaplastic gliomas and is significantly more prominent than in low grade astrocytomas (p = 0.001). Steroid therapy substantially reduced the amount of FDG uptake in the one case studied both before and after its administration. The difference in FDG uptake between steroid-treated and untreated cases of primary CNS lymphoma, however, did not reach statistical significance (p = 0.40). Primary CNS lymphoma, like gliomas, suppresses the metabolism of both contiguous and distant but functionally linked areas of the brain. This study thus shows that the metabolic behavior of primary CNS lymphoma, as monitored by FDG-PET, resembles that of malignant glial tumors.