ISPUB.COM The Internet Journal of Nuclear Medicine Volume 5 Number 2 1 of 4 The Value of FDG PET/CT Imaging in Dermatomyositis As A Paraneoplastic Syndrome in Malignancy Suspicion T Ones, M Aras, F Novruzov, F Dede, S Inan?r, T Erd?l, H Turoglu Citation T Ones, M Aras, F Novruzov, F Dede, S Inan?r, T Erd?l, H Turoglu. The Value of FDG PET/CT Imaging in Dermatomyositis As A Paraneoplastic Syndrome in Malignancy Suspicion. The Internet Journal of Nuclear Medicine. 2009 Volume 5 Number 2. Abstract Dermatomyositis (DRM) is a polymyositis accompanied by skin inflammation. It may be seen in various types of cancers as a paraneoplastic syndrome. A 45-year-old male presented with DRM which F-18 flourodeoxyglucose PET/CT (FDG PET/CT) revealed intense hypermetabolic nodule in the right lung and multiple mediastinal LAPs which were previously underestimated in diagnostic CT. The nodule was later biopsied and reported as lung cancer. After chemotherapy treatment the typical skin findings for DRM (Paraneoplastic Syndrome) was disappeared. FDG PET/CT seems to be a usefull method for cancer screening in DRM patients. INTRODUCTION Dermatomyositis (DRM) is a clinical syndrome of unknown cause involving the skeletal and myocardial muscles. Five basic diagnostic criteria of DRM are; symmetrical proximal muscle weakness, abnormal muscle biopsy, increased skeletal muscle enzymes, abnormal electromyography and typical skin findings with or without dysphagia and shortness of breath (1). A recent population-based study from Mayo Clinic found the incidence of dermatomyositis to be 13.98 per million in women and 4.68 per million in men (2). DRM may be seen with primary rheumatologic syndromes and in various types of cancers as paraneoplastic syndrome. First, in 1916 Stertz showed the relationship between gastric cancer and DRM (3). It is thought that in patients with malignancy, DRM develops due to a reaction against cancer cells, but the pathophysiology of DRM could not be fully explained yet. 18-F flourodeoxyglucose PET/CT (FDG PET/CT) has been extensively used in tumor imaging recently. Although the role of FDG PET/CT in cancer screening is not well known, there are papers that recommended it as alternative to conventional methods. In this case report with a brief review of literature, we aimed to underline the importance of FDG PET/CT in cancer screening in DRM patients. CASE REPORT A 45-year-old male patient with ANA seropositivity and symptoms of DRM as a paraneoplastic syndrome was admitted to the dermatology service. His diagnostic thoracic CT revealed nodular lesion located in the superior-posterior segment of the lower lobe of the right lung without any other pathology. Whole body FDG PET/CT imaging was planned for the metabolic characterization of this nodule. FDG PET/CT demonstrated intense FDG uptake, not only in the suspected pulmonary nodular lesion (Fig.A, arrows), but also in multiple enlarged mediastinal lymph nodes (Fig.B, arrows).