Preoperative magnetic resonance imaging characteristics of oval circumscribed fast enhancing lesions in patients with newly diagnosed breast cancer

The aim of this study was to investigate the follow-up results and characteristics of oval circumscribed lesions with fast initial enhancement on preoperative magnetic resonance imaging (MRI) in patients with newly diagnosed breast cancer. Preoperative data from consecutive patients newly diagnosed with breast cancer between 2010 and 2013 were retrospectively reviewed. Only MRI reports containing, “oval shape, circumscribed margin, and fast initial enhancement,” were extracted and analyzed. Follow-up results and clinical and pathological findings were evaluated. A total of 430 oval circumscribed lesions with fast initial enhancement were included. Forty-eight lesions were pathologically confirmed at initial workup and 382 were followed up. Among the 48 lesions, 14 were found to have additional malignancy and 34 were benign. Among the 382 followed-up lesions, only 1 was subsequently confirmed to be malignant. There were no evident changes in any of the remaining lesions during follow-up. The overall rate of malignancy was 3.5% (15/430). When lesions exhibited delayed washout enhancing kinetics (P < .001), were located ipsilaterally (P = .007), and closer to the primary tumor (P = .012), the possibility of malignancy was high. High T2-weighted imaging signal intensity suggested benignity (P = .043). Although the probability of being diagnosed with malignancy during follow-up in this study was low (0.3%), this investigation revealed several preoperative MRI characteristics that should alert clinicians to the possibility of malignancy.