18 F-FDG PET and MRI Evaluation of Paraneoplastic Limbic Encephalitis.

Autoimmune limbic encephalitis (paraneoplastic or nonparaneoplastic) is a rare condition involving autoantibodies against intracellular or cell-surface proteins of neurons. Patients typically present with acute and progressive neuropsychiatric symptoms. Although the criterion standard for diagnosis remains detection of autoantibodies in cerebrospinal fluid, there are characteristic imaging features that can aid in diagnosis, notably abnormalities in the bilateral medial temporal lobes on imaging, particularly with nuclear imaging. Here, we present 18 F-FDG PET findings of paraneoplastic limbic encephalitis in a 65-year-old man.