PET imaging pitfall in recurrent oligodendroglioma with drug-resistant epilepsy: illustrative case.

BACKGROUND

MRI and PET imaging using radiolabeled amino acids offer a valuable adjunct for defining the extent of tumor growth in gliomas, assessing treatment response, and distinguishing true progression from pseudoprogression.

OBSERVATIONS: The authors report the case of a 37-year-old patient with intractable epilepsy and suspected recurrence of an oligodendroglioma. MRI revealed progressive gadolinium enhancement in the right frontal lobe, and both fluorethylthyrosine PET and translocator protein imaging demonstrated high tracer uptake in the same region, raising concern for tumor recurrence and progression. The patient underwent extensive resection of the right frontal lobe beyond contrast enhancement. Postoperatively, seizures were well controlled. Interestingly, histopathological analysis revealed predominantly normal brain tissue next to a limited area of tumor recurrence, demonstrating that the observed MRI and PET abnormalities were seizure-induced changes rather than tumor recurrence.

LESSONS: In patients with epileptic seizures, MRI and PET abnormalities may overestimate tumor recurrence and should be interpreted with caution. https://thejns.org/doi/10.3171/CASE25589.