Role of 18F-FDG PET/CT in clinical management of patients with myasthenia

Objectives To assess the role of 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in clinical management of patients with myasthenia.

Methods Between September 2010 and November 2013, 42 cases (27male 15 female; the average age is 63y) with myasthenia who underwent whole-body 18F-FDG PET/CT were enrolled in this study. The final diagnoses were based on histopathology.

Results Of the 42 patients, 18 (42.9%) had an abnormal FDG uptake. Of these 18 patients, 14 (78%) were histologically confirmed as having a malignancy including lung cancer (n=6), lymphoma (n=3), prostate cancer (n=1), breast cancer (n=1), renal cell cancer (n=1), POEMS (n=1) and colon cancer (n=1) , 18F-FDG PET/CT detected all the primary malignancies and metastases. The other 4 patients were histologically proved as inflammatory disease including dermatomyositis, polymyositis, myotenositis, immunoinflammatory peripheral neuropathy. 18F-FDG PET/CT was false - positive in a patient with immunoinflammatory peripheral neuropathy.

Conclusions 18F-FDG PET/CT is helpful to find the causes of myasthenia. 18F-FDG PET/CT can demonstrate the underlying malignancy, provide the biopsy site and determine the extent of disease involvement.