Stromal Fibrosis of the Breast: A Spectrum of Benign to Malignant Imaging Appearances

OBJECTIVES: The aim of this study is to demonstrate the various imaging appearances of stromal fibrosis on mammography, ultrasound, and magnetic resonance imaging (MRI). MATERIAL AND METHODS: This study included 75 female patients who presented to the American University of Beirut Medical Center between January 2010 and October 2015 for breast imaging. 66 (88%) patients obtained a mammogram, 71 (95%) had an ultrasound, and 6 (8%) had an MRI. Patients included had stromal fibrosis proven on biopsy. RESULTS: The most common finding on mammogram was calcifications which was present in 14 (21%) patients, while on ultrasound it was a mass which was present in 61 (86%) patients. A mass was detected on MRI in 2 (33.5%) patients. Most lesions detected had benign findings such as masses with circumscribed margins. We had a follow-up for 53 (71%) patients with an average follow-up interval of 28.5 months (range: 5 – 70). Increase in size of the index lesion was noted in only 2 patients; upon rebiopsy, pathology results read stromal fibrosis for one lesion and fibroadenoma for the other. The remaining lesions were either stable or decreased in size. The higher detection rate of a mass on ultrasound was statistically significant (p<0.001) in comparison to that of mammography. CONCLUSION: Stromal fibrosis can have various presentations on imaging from benign to suspicious for malignancy features. In the case of accurate targeted biopsy, when stromal fibrosis is diagnosed, the result can be considered concordant. Therefore, such lesions can be followed up by imaging to document stability and confirm benignity.