Objective: Distinguishing benign inflammatory from malignant processes is a diagnostic dilemma especially in a tuberculosis (TB)-endemic country like China.Tuberculosis (TB) is a common worldwide infection and a medical and social problem causing high mortality and morbidity,especially in developing countries.The aim of the study is to analysis the pitfalls of 60 cases tuberculosis mimicking malignancy by 18F fluorodeoxyglucose (FDG) positron emission tomography/computer tomography (PET/CT) scan.Methods: 60 patients with tuberculosis, who underwent whole-body 18F-FDG PET/CT, were enrolled retrospectively.The inclusion criteria are the following: (a) There is not a conclusive diagnosis before the PET/CT scan.(b) PET/CT impression is malignant or most likely malignant.(c) The final pathology result or follow-up clinical diagnosis is tuberculosis.Imaging protocols:The images of whole body were acquired at 60min after administration of 222~555MBq 18F-FDG.The PET/CT imaging characteristics and clinical data, including lesion size, distribution,standardized uptake value(SUV) and the ratio of misdiagnosis of 60 tuberculosis (50 confirmed pathologically and 10 clinically) were retrospectively analyzed.Following the whole body scan of PET/CT, each patient had a chest spiral CT scan with hold breathing about 10sec was performed for detailed observation of lung lesions.Contrast enhanced CT (CECT) was performed in 8 patients.Results: ①The 30cases were misdiagnosised as lung cancer, 14cases as malignant lymphoma,6cases as malignat mesothelioma, 3cases as intestine carcinoma, 2cases as bone malignancy, 1 case as hepatoma, spleen malignancy, ovarian cancer, laryngocarcinoma and nasopharyngeal carcinoma respectively.②serum CEA and CA199 are in the normal level in all patients great majority.Elevated serum CA125 are found in the patients with ascites, pleural fluid or/and pericardial effusion.③Active tuberculosis accumulated 18F-FDG led to interpret as false-positive for malignancy.Pulmonary tuberculomas was without burs showed in chest spiral CT scan with breath hoding and without lymphadenomaphy in hili and mediastinum in mostly patients.The most common site of tubercular lymphadenopathy was cervical part, followed by retroperitoneal space, supraclavicular fossa, mediastinum, and hilum of lung, while axillary fossa and inguinal region were involved seldom.CECT had distinct significance owing to showing peripherally enhancing necrosis in tubercular lymphadenomaphy.Conclusion: The imaging features of tuberculosis are diverse and are prone to misdiagnosised to malignancy.It is important for radiologists and nuclear medicine physicians to recognize the common imaging features and patterns of tuberculosis in order to raise the possibility in the appropriate clinical setting.Incorporation of chest spiral CT scan with breath holding and CECT into the PET/CT protocol may improve the diagnostic confidence.