NIMG-78. THE ROLE OF FDG PET/CT IN MANAGING DIFFUSE MIDLINE GLIOMA WITH H3K27M MUTATION: A CASE STUDY AND PATHOLOGICAL CORRELATION

Abstract The clinical utility of fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) in the management of high grade gliomas has been a topic of ongoing debate, with limited cases reported that correlated FDG PET/CT findings with pathology, particularly in diffuse midline glioma with HdK27M mutation cases. We present the case of a 24-year-old male patient with diffuse midline glioma with H3K27M mutation centered in the left thalamus. Head FDG PET/CT was used for clinical management decisions with pathological correlation. Patient had stable follow up brain magnetic resonance images(MRIs) after initial Stupp protocol treatment comprised 6-week radiation therapy with concurrent temozolomide, followed by 12 cycles of adjuvant temozolomide. Despite stable MRI scans, subsequent evaluation using FDG PET/CT demonstrated a high standardized uptake value (SUV) of 13.8 that prompted craniotomy and partial resection of the lesion to confirm tissue diagnosis. Pathological findings confirmed the persistence of densely cellular malignant glioma, but with Ki-67 proliferation index of 4-5%. Following the surgery, the patient was closely monitored with surveillance MRIs for approximately four months post-surgery and follow up MRI’s showed slow growth of the tumor prompting additional therapeutic interventions. This case is an example of FDG PET/CT and pathological correlation and highlights the potential role of FDG PET/CT as an adjunctive imaging tool in the management of high grade gliomas.