Lewy Body Dementia Associated with Anti-IgLON 5 Encephalitis Detected on 18F Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography and 99mTc-TRODAT Single-Photon Emission Computed Tomography/Computed Tomography.

We present a case of Anti-IgLON 5 encephalitis with Lewy body dementia. 18F fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) scan and 99 mTc-TRODAT-1 SPECT/CT scan were done. 99 mTc-TRODAT-1 scan findings revealed severely reduced concentration of dopamine transporter in bilateral basal ganglia, suggestive of a degenerative parkinsonian disorder. 18F-FDG PET scan findings were suggestive of moderate-to-severe hypometabolism in the bilateral parieto-temporal and bilateral occipital cortices including the primary visual cortices, supporting Lewy body spectrum disease with associated hypermetabolism in the bilateral sensorimotor cortices, bilateral basal ganglia, thalami, brain stem, and bilateral cerebellar hemispheres suggestive of inflammatory pathology.