Mammotome core biopsy for mammary microcalcification: Analysis of 160 biopsies from 142 women with surgical and radiologic followup

BACKGROUND. Although stereotaxic fine-needle aspiration biopsy or core biopsy (14-gauge) have proven to be accurate techniques for the evaluation of mammographically detected microcalcification, the development of the Mammotome Biopsy System (Biopsys Medical, Inc., Irvine, CA) has led many medical centers to use this vacuum-assisted device for the sampling of microcalcification. METHODS. One hundred forty-two women underwent 160 stereotaxic Mammotome core biopsies of mammographic calcification over a 1-year period. The stereotaxic procedure was performed by radiologists using the Mammotome Biopsy System. Microcalcification was evident on specimen radiographs and microscopic slides in 99% of the cases. Excisional biopsy was recommended for diagnoses of atypia or carcinoma. Patients with benign diagnoses underwent mammographic followup. RESULTS. One hundred thirty-two benign, 12 atypical, and 15 adenocarcinoma diagnoses (comprising 1 lobular adenocarcinoma in situ [LCIS], 1 invasive ductal adenocarcinoma [IDC], and 13 intraductal adenocarcinomas [DCIS]: 10 comedo, 1 cribriform, 2 mixed cribriform and micropapillary) were rendered. Surgical excision in eight patients with atypia on Mammotome biopsy (two refused surgery, two were lost to followup) showed ductal hyperplasia in three, atypical ductal hyperplasia (ADH) in three and DCIS (low grade, solid) in two patients. Surgical excisions in 14 patients diagnosed with carcinoma (1 patient lost to followup) showed ADH in 3, ADH and LCIS in 1, residual DCIS in 8, IDC in 1, and microinvasive carcinoma in 1 patient. CONCLUSIONS. A diagnosis of atypia on Mammotome biopsy warranted excision of the atypical area, yet the underestimation rate for the presence of carcinoma remained low. The likelihood of an invasive component at excision was low for microcalcification diagnosed as DCIS on Mammotome biopsy. Mammotome biopsy proved to be an accurate technique for the sampling and diagnosis of mammary microcalcification.