Stromal fibrosis of the breast

OBJECTIVE. The purpose of this retrospective study was to describe the. ima ging 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 vari able in appearance. Most of the sonographic lesions were indeterminate, wit h 16 (25%) of 64 showing suspicious features. Discordant imaging resulted i n three patients having a second core biopsy and nine patients having an ex cisional biopsy. The two false-negative findings were the result of an infi ltrating 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 sugges ts that patients diagnosed at core biopsy as having stromal fibrosis can be treated conservatively with a short-term follow-up protocol. However, it w ould be prudent to continue to recommend either a second core biopsy or an excisional biopsy for imaging features that cannot be reliably differentiat ed from malignancy.