[Preoperative assessment of asymptomatic adnexal tumors by positron emission tomography and F 18 fluorodeoxyglucose].

AIM: To evaluate use of F-18-FDG-PET in assessment of dignity of asymptomatic adnexal masses.

METHODS: 85 asymptomatic patients with suspicious, asymptomatic adnexal masses were evaluated. Static FDG-PET (Exact HR+ or ECAT 931) imaging of the abdomen was performed following application of 222-555 MBq F-18-FDG. Iterative reconstruction was applied. PET data were analysed visually, at first without and second together with MRT images. Final diagnosis was made by histopathology.

RESULTS: FDG-PET allowed correct identification of 4 of 8 malignant adnexal tumors. False negative results were obtained in 2 adenocarcinomas stage pT1a and 2 borderline-tumors. In 60 out of 77 benign adnexal masses malignancy could be excluded. False positive FDG-uptake, partly because of misinterpretation of gastrointestinal activity, was found in 3 inflammatory processes, 1 teratoma, 1 benign schwannoma, 1 dermoid cyst, 1 benign thecoma, 1 serous cyst, 1 serous cystadenoma, 2 mucinous cystadenomas, 2 corpus luteum cysts, 3 endometriosic cysts and 1 sactosalpinx. The overall sensitivity and specificity of FDG-PET alone were 50% and 78%. Evaluation together with MRT images showed a sensitivity of 50% and a specificity of 86%.

CONCLUSION: Sensitivity of FDG-PET in detection of borderline-tumors and early stage ovarian cancer seems to be limited. Low incidence of malignant ovarian tumors requires for assessment of dignity a procedure of high specificity, that is not reached by FDG-PET neither without nor together with MRT images for topographic orientation. Therefore use of FDG-PET for assessment of dignity in suspicious, asymptomatic ovarian tumors is limited.