Characteristics and outcome of enhancing foci followed on breast MRI with management implications

Abstract

Aim: To evaluate the risk of cancer of an enhancing focus identified at breast magnetic resonance imaging (MRI) by determining the positive predictive value (PPV) associated with specific characteristics of an enhancing focus.

Materials and methods: Retrospective, institutional review board-approved review of the database identified 111 consecutive patients who underwent short-term follow-up of 136 enhancing foci in 2008. Kinetic analysis (delayed enhancement pattern) and other characteristics, such as interval change and T2 signal intensity, were evaluated to calculate the PPV for malignancy.

Results: The overall malignancy rate of an enhancing focus was 2.9% [4/136, 95% confidence interval (CI): 0.9-7.6%]. Kinetic analysis showed no statistical difference in PPV between foci with washout enhancement [5.1% (2/39)] versus persistent enhancement [3.2% (2/62); Fisher's exact test, p = 0.6180]. PPV of a T2 hypointense focus was 8.7% (4/46); PPV of a new focus was 13.6% (3/22); PPV of an enlarging focus was 6.7%, (1/15). The combination of a focus being new and T2 hypointense had the highest PPV for malignancy (27.2%, 3/11, 95% CI: 9.2-57.1%).

Conclusion: Kinetic analysis was not specific for malignancy and should not be used solely to guide management. A new enhancing focus with T2 hypointensity had a high PPV for malignancy and may warrant immediate biopsy.