An area of high signal on FLAIR within the left mesial temporal structures and extending along the body of the left hippocampus has positive mass effect. No contrast enhancement or elevated cerebral blood volume (CBV) is identified. Spectroscopy suggests decreased NAA and increased myoinositol. Right-sided mesial temporal structures are normal. Minor periventricular and subcortical white matter disease. No acute diffusion changes.
Conclusion: Infiltrative lesion with mass effect involving left mesial temporal structures and extending along the body of the left hippocampus, most likely representing a low-grade glioma. DDx paraneoplastic encephalitis.