Abstract: Abstract Objective: To retrospectively evaluate whole body 18F-FDG PET/CT in depicting the primary tomors in cervical metastatic adenocarcinoma of unknown primary site. Methods: Seventeen patients were included and underwent whole body PET/CT imaging. The primary tumors and metastases were detected by visual evaluation and measurements of standardized uptake values.The PET/CT impression was verified by histopathology and/or follow-up. Results: In 17 patienis，primary tumors of 13 patients were confirmed by pathological or clinical follow-up. Among them，8 were in the lung, 1 in breast, 1 in renal, 2 in colon and 1 in cervix. Among the other 4 cases, PET/CT correctly diagnosed 3 cases diagnosed metastatic adenocarcinoma previously but demonstrated as malignant lymphoma finally. The sensitivity, specificity and accuracy of PET/CT in identifying primary tumors were 92.3%, 75.0%, 88.2%, respectively. After PET/CT examination, 10 patients (58.8%) were detected additional metastatic lesions which were missed previously. Conclusion: Whole body 18F-FDG PET/CT may be of relatively higher value in identifying the primary tumor in cervical metastatic adenocarcinoma of unknown primary site. It also may display tumor involvement extent.

Key words: Fluorodeoxyglucose, Primary tumor, Metastatic adenocarcinoma, Cervical