Brain FDG PET Findings Mimicking Limbic-predominant Age-related TDP-43 Encephalopathy

Limbic-predominant age-related TDP-43 encephalopathy (LATE) is a recently recognized neurodegenerative disorder that frequently affects elderly patients and is often misdiagnosed as Alzheimer's disease. It typically presents with mild memory impairment and disproportionate hippocampal atrophy. FDG PET commonly shows distinct medial temporal lobe hypometabolism, which differs from Alzheimer's disease. We report a case with FDG PET findings suggestive of LATE; however, CT and MRI revealed hippocampal sulcus remnant cysts instead of hippocampal atrophy. This highlights the critical importance of correlative imaging in distinguishing LATE from other conditions with similar PET findings.