Abstract:

Objective: To investigate the image characteristics of ¹⁸F-fluorodeoxyglucose (¹⁸FDG) positron emission tomography and computer tomography(PET/CT) in the patients with dermatomyositis (DM) or polymyositis (PM)associated with malignancy,and to provide basis for the diagnosis of DM/PM. Methods: The clinical data of inpatients diagnosed with DM/PM during 2009 to 2015 in Peking Union Medical College Hospital were collected.The clinical manifestations and ¹⁸FDG PET/CT wholebody scan were analyzed in the 17 patients with DM/PM complicated with tumor and 39 patients with DM/PM without tumor. Results: Among 56 patients with DM/PM,17 patients were complicated with maglignant tumor; there were 5 patients with lymphoma, 7 patients with lung cancer, 1 patient with thyroid carcinoma, 1 patient with breast cancer,1 patient with cervical carcinoma, 1 patient with neuroendocrine tumor of liver,and 1 patient with thymoma.The maximal standard uptake value(SUVmax) of malignant lesions was 1.47-22.93(7.67±6.60).There was diffuse increase of ¹⁸FDG uptake in the muscles in 22 patients,and the SUVmax was 0.71-2.93(1.43±0.68); there were 9 patients(40.91%)associated with malignancies.There was local increase of ¹⁸FDG uptake in the muscles in 26 patients,and the SUVmax was 1.06-8.74(2.62±1.65). There were 6 patients(23.08%)associated with malignancies.There was normal level of ¹⁸FDG uptake in the muscles in 8 patients; There were 3 patients(37.50%)associated with malignancies. There was 15 patients with interstitial pneumonia,and 2 patients(13.33%)associated with malignancies. Conclusion: The ¹⁸FDG PET/CT image of tumor-associated DM/PM has the certain characteristics.The patients with diffuse increase of ¹⁸FDG uptake in the muscles have the highest incidence rate of tumor.¹⁸FDG-PET/CT may become an effective method of assisted diagnosis for the patients with suspected DM/PM.

Key words: dermatomyositis, malignant neoplasms, positron emission tomography, fluorine-18 fluoro-deoxyglucose, tomography,X-ray computed