10.22376/ijpbs.2019.10.1.p1-12 Volume 15 Issue 3 July-September Adnexal masses are commonly detected during imaging studies and are a common indication for exploratory surgery. Accurate assessment of adnexal mass helps to triage patients and prompt referral. Extensive surgery should be performed in an oncology centre as surgical staging is a critical prognostic parameter in ovarian malignancy. The main objective of this study was to assess the utility of the risk of malignancy index four (RMI-4) in predicting malignancy in ovarian mass. Retrospective study of adnexal mass patients who underwent primary surgery. RMI 4 was determined. Response operating curve (ROC) was used to analyse the usefulness of the RMI4 score in predicting benign from malignant lesions. A total of 117 patients with adnexal masses, of which, based on pathology reports, 101 patients (86.3%) had malignancies, 11 patients (9.4%) were benign, and 5 patients (4.3%) were borderline. Serous cystadenocarcinoma (n=76) was the most common malignant lesion. The serum concentration of CA125 in benign neoplasms was 28.5 with a range of 4 to 290 U/mL, while in malignant tumours, the CA 125 was 239.8 (3.4 to 11750) U/mL. The mean RMI 4 value in malignant lesions was 14896, ranging from 870 to 752000. The RMI 4 had a sensitivity of 94% and a specificity of 62.5%. The positive predictive value of RMI4 is 94.1%, and the negative predictive value is 62.5%, with an accuracy of 89.74%. RMI 4 can be a useful tool for the initial assessment of patients with pelvic masses, and women with adnexal masses can be referred promptly to gynaecologic oncologists for early management. Ramani Gangadharan Ashitha, AdarshDharmarajan and Sanjay Badesara RMI 4, CA 125, Adnexal mass, ROC curve 9-14