Stromal fibrosis of the breast: outcome analysis

Stromal fibrosis in the breast is a non-specific benign pathologic entity with wide spectrum of imaging finding. The false-negative rates (number of cancers missed) previously reported have limited value because short follow-up period and small number of populations.

To describe the mammographic and sonographic findings of stromal fibrosis of the breast diagnosed by imaging-guided biopsy and to determine the false-negative rate at percutaneous biopsy.

Between January 2007 and December 2008, 3097 consecutive imaging-guided breast core biopsies were performed. Patients were included in our study if stromal fibrosis was the predominant pathologic finding. Patients who had received <2 years of follow-up were excluded. Mammographic and sonographic findings were reviewed. Follow-up imaging for >2 years and histologic data were reviewed to evaluate lesion stability.

Stromal fibrosis was diagnosed in 187 (6.0%) of 3097 imaging-guided biopsies among patients with >2 years of follow-up (mean, 41.9 months). Among them, 91 (49%) of 187 lesions were not visible on mammography and calcifications were the most common findings, being identified in 33 lesions (17.6%). The most common sonographic finding was an oval hypoechoic mass with a circumscribed margin. Forty-two lesions (22.5%) were excised. Four false-negative lesions (2.1%, 4/187) were identified; all false-negative lesions were diagnosed within 6 months because of imaging-pathology discordance (75%, 3/4) or disease progression (25%, 1/4).

Stromal fibrosis diagnosed by imaging-guided biopsy has a wide spectrum of imaging finding and can be managed safely with radiologic-pathologic correlation and subsequent short-term imaging follow-up.