[Digital stereotactic breast microbiopsy with the mammotome: study of 122 cases]

To evaluate the diagnostic value of vacuum-assisted biopsy (VB) with digital stereotactic Mammotome on dubious mammary lesions clinically and sonographically negative as an alternative to surgical biopsy diagnosis.

From November 1999 to November 2000, 122 biopsies were performed using a vacuum suction aspiration device with digital stereotactic-guided Mammotome (Fischer prone table) on 116 patients between the age of 34 and 74 years (median 51 yrs). Sampling was performed with an 11 gauge probe. All patients were previously subjected to mammography in which dubious lesions were evidenced without clinical and sonogram confirmation. All lesions that were obviously benign or malignant were excluded. Mammography demonstrated isolated microcalcifications, small opacities and parenchymal distortions. Microcalcifications were then subdivided into lobular, rad-shaped, granular, mixed and pulverulent, according to Tabar's classification. The median diameter of lesions was 13 mm (range 3-50). The median number of Mammotome biopsy samples was 10.8 (range 3-19). All samples were radiographed and magnified. In 76 patients, the Mammotome biopies were incisional (only a part of the lesion was removed) and in 46 the biopsy was excisional (the entire lesion was removed). The biopsy site was marked with a non-magnetic metallic clip in 83 patients. Slight bleeding was noted during the procedure in two cases. Ultrasound visualization evidenced a hematoma at the biopsy site in one patient which was successfully resolved in one month with local therapy. No noticeable pain or patient intolerance to the procedure was observed.

Histological probe sample examination was negative in 91 patients (74.6%) and positive in 31 patients (25.4%). The benign histologies included adenosis and epitheliosis (47 pts), sclerosing adenosis (7 pts), fibroadenoma (7 pts), fibrosis and fibrocystic mastopathy (30 pts). Of the 31 positive patients, 14 were infiltrating carcinomas (45%) and 17 ductal carcinomas in situ (DCIS) (55%). All positive cases underwent surgery. The post-surgical histological examination confirmed all diagnoses of infiltrating carcinoma while the diagnosis of DCIS was confirmed in 15 cases; infiltrating microfoci associated with DCIS were evidenced in two cases.

VB with digital stereotactic Mammotome was shown to be a valid method for dubious mamographic lesions in which cytology often supplies an inadequate or false-negative responses. This method distinguishes between benign and malignant lesions rapidly without discomfort to the patient, thus reducing the number of diagnostic surgical biopsies. Moreover, in positive cases, it offers the advantage of avoiding extemporaneous intraoperative procedures and the possibility to perform biological tests on the tumor before surgery (estrogen and progesterone receptors, HER-2 neu, grading, Ki 67, p53 ), thus providing patient benefits and a distinct reduction of costs. However, this method is purely diagnostic and is not sufficient for therapeutical purposes.