Cancer frequency detected by positron emission tomography-computed tomography in limbic encephalitis

Abstract Objective Paraneoplastic limbic encephalitis (LE) occurs frequently with considerable variability according to literature reports. We thus determined the cancer frequency in mixed LE subtypes sharing the diagnosis of temporal lobe epilepsy (TLE). Methods All patients underwent magnetic resonance imaging (MRI) of the brain, electroencephalography (EEG) recordings, neuropsychological testing, immunohistochemistry, and clinical examination together with whole body 2-fluor-2-desoxy- d -glucose (FDG)-positron emission tomography (PET)/computed tomography (CT) to detect cancer in this observatory study. Results Ninety-three patients (median: 52 years) with TLE due to autoimmune LE were investigated. Cancer was detected in the FDG-PET/CTs of 3 out of 93 (3.2%) patients with LE. Cancer was diagnosed upon, 5 years earlier and 5 years after FDG-PET/CT in 7 of 93 (7.5%) of all patients with LE. The cancer frequency in those patients was significantly lower than that reported in the largest series of patients with LE associated with and without different antibodies (7.5% vs. 23.5%, Bootstrap test, p  Conclusions Our findings reveal that the cancer frequency in patients with TLE with LE detected by FDG-PET/CT is low and not different from the age-dependent natural cancer occurrence in a regional population.