risk of malignancy index as an evaluation of preoperative pelvic mass

background: risk of malignancy index (rmi) is the best method for discriminating benign and malignant pelvic masses. the aim of this study was to determine the rmi for preoperative evaluation of pelvic mass. methods: this study was performed on 182 women with adenexal mass referred to yahyahnejiad hospital of babol university of medical sciences in iran from 2007 to 2009.the sensitivity, specificity, positive (ppv) and negative predictive values (npv) of menopausal status, ultrasound finding of pelvic mass and level of serum ca-125, separately or combined into the rmi were calculated and compared. results: the mean age of patients was 39.9±9.3 years. the rmi with the cut-off point of 265 had a sensitivity of 91.3%, specificity of 96.2 %, ppv of 77.7% and npv of 98.7% for diagnosis of malignant masses. conclusion: risk of malignancy index should be an effective method for evaluating a patient with adnexal masses before operation and a cut-off point of 265 which has a very high sensitivity, specificity and positive and negative predictive values for discriminating malignant and benign pelvic masses.