Value of 18F-FDG PET/CT in the detection of occult malignancy in patients with dermatomyositis

Aim: Dermatomyositis (DM) is an inflammatory myopathy in adults that is strongly associated with malignancy. The aim of this study was to evaluate whether whole-body F-18-FDG PET/CT imaging can offer a standard option searching for underlying malignancy in DM patients. Methods: Seventy-five patients diagnosed with DM were referred to our department for whole-body F-18-FDG PET/CT to determine whether the patients suffered from malignant tumor. All PET images were analyzed by two experienced nuclear medicine physicians separately. Results: According to the F-18-FDG PET/CT results, 19 patients were suspected to suffer from malignant tumor, then biopsy was performed. Of the 19 patients, 17 patients were confirmed to have malignant tumor. The pathological types were: nasopharyngeal carcinoma, rectal cancer, lung cancer, colon cancer, gastric cancer, gallbladder cancer, kidney cancer, ovarian cancer, breast cancer, lymphoma and vertebral metastatic adenocarcinoma of unknown origin. No malignancy was found for the 56 PET-negative patients during follow-up. For the age between 17 patients with malignancy and 58 patients without malignancy, no significant difference was observed. Conclusion: F-18-FDG PET/CT may be a sensitive and effective method in determining whether the patients with DM suffered from malignant tumor.