Objective: The purpose of this retrospective study was to describe the imaging features of stromal fibrosis of the breast and to determine the false-negative rate (number of cancers missed) at percutaneous biopsy.
Materials and methods: Between January 1997 and October 1999, 1095 imaging-guided core biopsies were performed. Patients were included in our study if stromal fibrosis was the predominant histologic finding. Cores adjacent to previous excisional biopsies or from calcified lesions were excluded.
Results: Stromal fibrosis was diagnosed in 74 (6.8%) of 1095 imaging-guided core needle biopsies in 73 patients. The 10 mammographic lesions were variable in appearance. Most of the sonographic lesions were indeterminate, with 16 (25%) of 64 showing suspicious features. Discordant imaging resulted in three patients having a second core biopsy and nine patients having an excisional biopsy. The two false-negative findings were the result of an infiltrating lobular carcinoma and an infiltrating ductal carcinoma, the latter diagnosis delayed for 6 months.
Conclusion: The low incidence (2.7%) of missed cancers in our series suggests that patients diagnosed at core biopsy as having stromal fibrosis can be treated conservatively with a short-term follow-up protocol. However, it would be prudent to continue to recommend either a second core biopsy or an excisional biopsy for imaging features that cannot be reliably differentiated from malignancy.