Objective: Multiple fibroadenomas (MFA) of the breast is a rare benign disease, thus its natural history is poorly understood. The aim of our study was to describe the radiological evolution of MFA, and to evaluate the influence of different factors on this evolution.
Methods: This was a longitudinal cohort study. All patients included had two clinical and radiological assessments (breast ultrasound (US) and magnetic resonance imaging (MRI)) at least 5 years apart.
Results: Seventy-two women were followed for 7.6 ± 2.1 years. The radiological evolution showed a decrease in the number of fibroadenomas (FA) in almost 40% of cases on the MRI and in 52% of cases on the US. There was a decrease of size in 92% of cases. An increase in the number of FAs was found in about 40% of cases with, for the majority, a decrease of size (73.1% by US and 89% by MRI). Older age at the 1st FA (p<0.0001) and at the diagnosis of MFA (p<0.0001), pregnancy (p=0.003) and progestin use (p<0.001), particularly lynestrenol (p<0.0001), had a beneficial effect on the evolution of MFA.
Conclusion: This is the first longitudinal study describing women with MFA. The radiological evolution of MFA seamed favorable and similar to that expected for a single FA. We identified factors influencing the evolution of the disease, including progestin treatments such as lynestrenol, which could have a beneficial effect. Our cohort should be followed further in order to expand our knowledge of MFA, especially concerning the risk of breast cancer.