Background parenchymal enhancement: is it just an innocent effect of estrogen on the breast?

We aimed to retrospectively analyze whether background parenchymal enhancement (BPE) on breast magnetic resonance imaging (MRI) correlates with menarche, menopause, reproductive period, menstrual cycle, gravidity-parity, family history of breast cancer, and the Breast Imaging-Reporting and Data System (BI-RADS) category of the patient. The study included 126 pre- and 78 postmenopausal women who underwent breast MRI in our institute between 2011 and 2016. Patients had filled a questionnaire form before the MRI. Two radiologists blinded to patient history graded the BPEs and the results were compared and analyzed. The BPE was correlated with patient age and the day of menstrual cycle (P < 0.01 for both). No correlation was found with menarche age, menopause age, total number of reproductive years, and family history of breast cancer. In the moderate BPE group, only 1 out of 35 patients and in the marked BPE group only 1 out of 13 patients were postmenopausal and had BI-RADS scores of 4 and 5, respectively. Increased symmetrical BPE is mainly due to current hormonal status in the premenopausal women. High-grade BPE, whether symmetrical or not, is rarely seen in postmenopausal women; hence, these patients should be further investigated or closely followed up.