Biopsy of amorphous breast calcifications: pathologic outcome and yield at stereotactic biopsy

To assess the pathologic outcome of amorphous breast calcifications and the success of stereotactic biopsy for such lesions.

From July 1995 through February 2000, biopsy of all clustered amorphous calcifications not clearly stable for at least 5 years or in a diffuse scattered distribution was recommended. Logistic regression analysis was used to stratify the risk of malignancy by patient risk factors, calcification distribution, and stability.

Calcifications were retrieved from 150 biopsies; 30 (20%) proved malignant and included 27 ductal carcinomas in situ and three low-grade invasive and intraductal carcinomas (2-5 mm). Another 30 (20%) yielded high-risk lesions, including 21 atypical ductal hyperplasia, eight atypical lobular hyperplasia, and one lobular carcinoma in situ. In 150 lesions, stereotactic biopsy was performed on 113 and aborted in 10. Calcifications were retrieved from all 113 stereotactic biopsies. Of those with calcification retrieval, there were three histologic underestimates (accuracy, 97%). Stereotactic biopsy spared a surgical procedure in 57 (46%) of 123 patients. Needle localization was required for 23 (15%) of 150 patients due to poor conspicuity. Five (45%) of 11 biopsies performed in women with ipsilateral breast cancer showed malignancy (P = .025). When multiple lesions of amorphous calcifications were present in one breast, sampling of one reliably predicted the outcome of others.

We found a substantial rate of ductal carcinoma in situ and high-risk lesions associated with amorphous calcifications. Stereotactic biopsy can be successfully performed for the majority of subtle amorphous calcifications; however, only a minority were spared a surgical procedure.