18f-fluoroethyl-l-tyrosine and Central-Nervous-System-Diseases

We present a 45-year-old man with newly generalized tonic-clonic seizures due to a contrast-enhancing frontal lesion with perifocal edema suggestive for high-grade glioma (HGG). For further evaluation, a dynamic F-FET PET scan was performed, which showed high F-FET-uptake with early peak and constantly decreasing time-activity curves, a characteristic feature of HGG. Stereotactic biopsy and histological evaluation excluded a neoplastic lesion but confirmed a manifestation of neurosarcoidosis with strong expression of the L-amino-acid-transporter considered responsible for F-FET-uptake. Therefore, unknown manifestations of neurosarcoidosis represent a clinical pitfall in F-FET PET and can mimic HGG.

Topics: Brain Neoplasms; Central Nervous System Diseases; Diagnosis, Differential; Glioma; Humans; Male; Middle Aged; Positron Emission Tomography Computed Tomography; Radiopharmaceuticals; Sarcoidosis; Tyrosine