Diagnostic Value of the O-Rads Ultrasound Classification System for Detecting Malignant Adnexal Lesions Using Histopathology as Gold Standard

Abstract

Adnexal masses are common clinical findings in gynecological practice. Clear differentiation between benign and malignant lesions is essential for appropriate referral and treatment. Using histopathology as the gold standard, this study aimed to determine the diagnostic value of the O-RADS classification system on ultrasound for detecting malignant adnexal lesions. This cross-sectional diagnostic accuracy study was conducted at the Department of Radiology, Chughtai Healthcare, Lahore, Pakistan, from May 2026 to August 2026. A total of 390 women aged 15–60 years with suspected malignant adnexal lesions scheduled for surgery were enrolled using non-probability consecutive sampling. Pelvic ultrasonography was performed, and adnexal lesions were classified according to the O-RADS US system. The mean age of the participants was 41.8±11.2 years, mean BMI was 27.1±4.8 kg/m², and mean duration of symptoms was 6.4±3.7 months. Histopathology confirmed malignancy in 107 (27.4%) women and benign lesions in 283 (72.6%). O-RADS ultrasound classified 132 (33.8%) lesions as positive and 258 (66.2%) as negative for malignancy. There were 90 true-positive, 241 true-negative, 42 false-positive, and 17 false-negative cases. The sensitivity, specificity, positive predictive value, negative predictive value, and overall diagnostic accuracy of O-RADS were 84.1%, 85.2%, 68.2%, 93.4%, and 84.9%, respectively.  O-RADS ultrasound demonstrated good diagnostic performance for differentiating malignant from benign adnexal lesions, with a particularly high negative predictive value. The progressive increase in malignancy across higher O-RADS categories supports its value as a standardized preoperative risk-stratification tool.