Intérêt de la TEP/TDM au FDG dans l’investigation étiologique des syndromes paranéoplasiques

Paraneoplastic syndromes (PNS) represent a rare and heterogeneous group of entities whose clinical symptoms may sometimes antedate the diagnosis of the causative tumor. In the context, the identification of the underlying tumor becomes very important for the patient's functional and sometimes vital prognosis, by allowing an earliest treatment of the tumor. ¹⁸FDG PET/CT has become indispensable in the diagnosis and follow-up of numerous cancers but its role in etiological investigation of isolated paraneoplastic syndromes for the research of an occult tumor is not defined yet. Nevertheless, requests of PET/CT in this indication are frequent in nuclear medicine departments, with an uncertain diagnostic yield. We have listed retrospectively 64 patients, sent to nuclear medicine department of Nancy university hospital between 2004 and 2010 for the research of an occult tumor because of a clinically suspected paraneoplastic syndrome, in order to estimate its diagnostic contribution in this indication. According to our results, ¹⁸FDG PET-CT would be interesting by its negative predictive value concerning the tumoral risk, in keeping with its known sensitivity PET-CT may also present an interest for the diagnosis and the characterization of non-tumoral conditions generating symptoms initially wrongly suspected to be paraneoplastic.