We compared the tumor uptake of 11 C-methionine (MET) with positron emission tomography (PET) with the results of a pathological analysis to examine the proliferative potential and microvessel density measured with immunostaining for MIB-1 and factor VIII, respectively, from 33 patients with glioma. The MET uptake in oligodendrogliomas was significantly greater than that in grade 2 astrocytomas and comparable to those in grade 3 and 4 astrocytomas. The MIB-1 index of oligodendroglioma meanwhile was comparable to that of grade 2 astrocytoma. The microvessel area in oligodendroglioma was significantly greater than that in grade 2 astrocytomas and comparable to those in grade 3 and 4 astrocytomas. According to a multivariate statistical analysis, MET uptake ratio was closely correlated with the MIB-1 index among astrocytomas. An increase in the microvessel area in the oligodendrogliomas contributed to the higher MET uptake among the tumors with a low-proliferative index. This information is important for interpreting the results of MET-PET studies for clinical use.

Central neurocytomas are typically benign tumors that have high local control rates after gross total resection. Radiotherapy for residual or recurrent central neurocytomas is controversial. We report a 30-year-old male with a central neurocytoma in the lateral ventricle. The tumor was subtotally resected through a transcallosal approach, and subsequently treated with gamma knife radiosurgery. The tumor had shrunken markedly by 2 months after radiosurgery and remained unchanged during the one year follow-up period. Gamma knife radiosurgery may be an option for effective treatment of patients with residual or recurrent central neurocytomas.