18F-FDG PET/CT in the evaluation of patients suspected of paraneoplastic neurological syndrome

Objective: This study aimed to determine the diagnostic impact of F-18-FDG PET/CT based on the clinical features of paraneoplastic neurological syndrome (PNS). Material and methods: Multicenter retrospective and longitudinal study of patients with suspicion of PNS. The clinical picture was classified into classic (CS) and non-classic syndrome (NCS). After the follow-up, the definitive or possible diagnosis of PNS was established. The pictures that did not match any of the previous criteria were categorized as non-classifiable. The state of the onco-neural antibodies was studied. The PET/CT was classified as positive or negative for the detection of malignancy. The relationship between PET/CT findings and the final diagnosis was determined. The differences between variables (Pearson test X-2) and the relationship between the results of the PET/CT and the final diagnosis were analyzed. Results: A total of 64 patients were analyzed, classifying 30% as CS and 42% as NCS. After the follow-up, 20% and 16% of subjects were diagnosed as possible and definitive PNS, respectively. Positive onco-neural antibodies were found in 13% of the patients. A definitive diagnosis of PNS was associated with a positive PET/CT (P=.08). A significant relation between antibodies expression and final diagnosis of neoplasia (1)=.04) was demonstrated. The PET/CT correctly localized malignancy in 5/7 cases of invasive cancer. Conclusions: The PET/CT showed a higher percentage of positive results in patients with definitive diagnosis of PNS. Despite the low prevalence of malignancy in our series, the PET/CT detected malignancy in a significant proportion of patients with invasive cancer. (c) 2014 Elsevier Espana, S.L.U. and SEMNIM. All rights reserved.