18F-FDG PET/CT findings in fatal Balamuthia Mandrillaris encephalitis in brain stem: A case report.

We presented a case of a 66-year-old female whose initial symptom was headache without obvious inducement. The patient's condition progressed rapidly to a semi-coma state after symptomatic treatment. The 18F-FDG PET/CT scan revealed circular FDG hypermetabolism and central metabolic defect of the pons and left frontal lobe lesions. The combination of clinical findings, MRI, and Metagenomic next-generation sequencing (NGS) of cerebrospinal fluid led to the diagnosis of Balamuthia mandrillaris encephalitis. The patient died 5 days after discharge.