MASTECTOMY WITHOUT MALIGNANCY AFTER CARCINOMA DIAGNOSED BY LARGE-CORESTEREOTAXIC BREAST BIOPSY

Mammary carcinoma diagnosed by large-core stereotactic biopsy (LCSBB) is often followed by definitive surgery, We report on positive (malign ant) LCSBB followed by definitive surgery that failed to demonstrate m alignancy, Between January 1993 and August 1996, 206 women in our inst itution underwent LCSBB, Carcinoma was diagnosed in 45 patients (22%) of the 206 (ductal carcinoma in situ (DCIS), n = 12; invasive carcinom a, n = 33), Twenty-nine of the 45 patients subsequently underwent mast ectomy, and 8 of 45 underwent lumpectomy. In 34 (92%) of these 37 pati ents, carcinoma was demonstrated at follow-up surgery, but in 3 patien ts (8%), mastectomy failed to reveal carcinoma, The characteristics of these three patients are as follows: Patient 1 was a 58-year-old woma n with a nonpalpable 6- to 8-mm nodule revealed by a screening mammogr am, Three of 8 LCSBBs showed colloid carcinoma, but histologic examina tion of 50 paraffin blocks and radiographic examination of the mastect omy sample failed to reveal carcinoma Patient 2 was a 64-year-old woma n with a nonpalpable 6- to 9-mm nodule revealed by mammogram, Six of 1 2 LCSBBs showed tubular carcinoma, but histologic examination of 30 pa raffin blocks from her mastectomy sample failed to reveal carcinoma, P atient 3 was a 72-year-old woman with a history of DCIS, She had under gone a lumpectomy and radiotherapy, and she had suspicious ipsilateral microcalcifications. Two of 8 LCSBBs showed comedo DCIS, but histolog ic examination of 26 paraffin blocks and radiographic examination of t he mastectomy sample failed to reveal carcinoma. Possible explanations for a mastectomy without malignancy after carcinoma was diagnosed by LCSBB include removal of the entire lesion by LCSBB, inflammatory resp onse obliterating remaining tumor, false-positive core biopsy result, patient misidentification, inadequate sampling of the surgical specime n, and failure to remove the tumor, We outline a series of steps for t he pathologists to follow when confronted with such a case.