Relatively decreased 11C-methionine uptake within the anaplastic component of a mixed-grade oligodendroglioma.

A 56-year-old woman presented with a mixed-grade oligodendroglioma. On 11C-methionine [MET]-positron-emission tomography images, heterogeneous uptake of MET was demonstrated in the mass lesion. The part of the lesion with higher MET uptake was identified as an ordinary oligodendroglioma, whereas the part of the lesion with lower MET uptake was an anaplastic component of oligodendroglioma. With oligodendrogliomas, we should be aware of the possibility that MET uptake decreases paradoxically with an increased anaplastic component of oligodendroglioma cells.