The large right temporal lesion demonstrates contradictory findings. The lesion exerts significant mass effect and demonstrates enhancement on conventional imaging. The spectroscopy studies demonstrate a central lactate peak. No clear-cut elevation in choline was demonstrated. The pattern of enhancement is incomplete. The contradictory findings raise the possibility that this lesion may not be neoplastic in nature. Consider a tumofactive demyelinating lesion as well as neoplasm for this lesion.

The patient went on to have a biopsy. 

Pathology:

Histopathology and special stains are in favor of demyelinating disease process. Section show white matter changes exhibiting gliosis, reactive astrocyte and numerous lipid-laden macrophages.

Special stains (LFB-PAS & MBP) show loss of myelin and relative preservation of axons (NFP).