Impalpable breast lesions: stereotactic core biopsy with an ‘add-on’ unit

Stereotactic core biopsy (SCB) for impalpable breast lesions has advantages over stereotactic fine needle aspiration biopsy. There are fewer inadequate specimens, the confidence of a benign diagnosis is higher, and appropriate initial surgery can be planned when invasive carcinoma is found. SCB was performed on 200 patients using an add-on unit with a standard mammography machine. Large bore (14 gauge) biopsy needles were used. A benign process not requiring surgery was found in 61 patients; definite malignancy was shown in the core in 90 patients with a correct prediction of invasion in 89% of 53 invasive cancers. Forty-nine other patients were referred for surgery because the core histology showed atypia or findings suspicious of malignancy or because the histological result did not adequately correlate with the mammographic appearances. SCB using an add-on unit can produce results similar to those obtained using a dedicated prone biopsy unit, and is an appropriate investigation in patients with suspicious impalpable breast lesions in hospitals where prone tables are not available.