10109-COT-13 LONG-TERM FOLLOW-UP OF FLAIR HIGH LESION IN THE BRAIN

Abstract

Abstract AIM Incidental FLAIR (Fluid Attenuated Inversion Recovery) high-intensity lesion in the brain can be considered as IDH-mutant low-grade glioma (LGG). Differential diagnosis includes trauma, ischemic changes, demyelinating diseases, and other inflammatory diseases. The biopsy is sometimes high risk for a young patient or an asymptomatic patient with a lesion in the brain stem, motor or language area. Imaging intervals vary among hospitals and the method for regular follow-up for these cases has not been established. METHODS We have studied 26 patients with FLAIR high lesion from 2012 to 2022. In cases of suspected LGG, the biopsy was performed, when necessary, after consultation with the patient and family. Our neurosurgery team protocol was to perform PET-MRI at the first consultation, and if there was negative, we have scheduled MRI examination at the next visit in one month. Then, MRI was performed every 2-3 months for the first year and every 3-6 months thereafter. The clinical features of these FLAIR high lesion and their differentiations from LGG in our cases are examined. RESULTS Biopsy was performed in 5 cases, but no tumor was found. The male-to-female ratio was 7:19, which was more common in female. The median age at onset was 44 years (15-47 years), showing a bimodal distribution with peaks in younger and older individuals. Among 26 cases, 14 cases had been unchanged for more than 5 years. The median maximum lesion diameter was 17 mm (8-47 mm). An annual average increase of LGG has been reported to be 3-5 mm in (Pallud, 2010). There were no cases diagnosed as glioma in cases where no expansion was seen after 5 years or more. CONCLUSION In this study, the possibility of glioma was considered to be low for cases in which no expansion on MRI was seen after 5 years or more.