Missing Targets after Nipple-Sparing Mastectomy: A Multi-Disciplinary Approach to Avoid an Undesirable Outcome.

Mastectomies for nonpalpable lesions are performed without imaging guidance on the premise that all or most of the accessible breast parenchyma and the lesion are removed. However breast tissue can be left in the patient after mastectomy in certain anatomic locations—skin flap, nipple areola complex and outer periphery of the mammary gland— particularly in skin sparing mastectomy (SSM) and nipple-sparing mastectomy (NSM) procedures. The residual breast parenchyma can have a potential long-term and short-term consequence, namely to serve as a nidus for developing recurrent breast cancer and to harbor incompletely removed tumor or tumor site, respectively. We herein present four breast cancer patients, who were treated with NSM and required subsequent corrective surgeries after incomplete excision of the primary tumor, the tumor site or the marker clip (Table 1). There were 569 therapeutic mastectomies performed at our institution in the past 30 months. During this interval, we prospectively identified four cases (0.7%) in which the primary tumor or tumor site was not identified in the NSM specimens. All of these four patients subsequently underwent corrective surgeries to remove the retained lesions. In three cases, the corrective surgery specimens showed invasive carcinoma along with the adjacent marker clips. In one case, only the biopsy site and the adjacent marker clip were identified in the corrective surgery specimen. In SSM and NSM, the superficial margin between the breast tissue and the overlying skin envelope is an area of concern. Oftentimes, a dissection plane is not clearly delineated between the dermis and the subcutaneous fat, thus allowing residual breast tissue to remain in the patient. In Torresan et al.’s study, the prevalence of residual breast tissue as measured by the presence of terminal ductal lobular units identified in the skin envelope was seen in 25 (59.5%) of 42 patients who underwent SSM with immediate breast implant. In another study, the SSM showed the greatest percentage of residual glandular tissue at 20.7% vs the simple and modified radical mastectomy at 8.8% and 8.2%, respectively. The peripheral location of the tumors may also present a technical challenge for a conservative mastectomy. Two of the four retained lesions in our series were deeply located in the inner quadrants (cases 1 and 4); one in the axillary tail of the upper outer