Elizabeth Jennifer Watson MD, MPH, Abstract Co-Author: Nothing to Disclose

Elizabeth J. Sutton MD, Presenter: Nothing to Disclose

Girard Gibbons BA, Abstract Co-Author: Nothing to Disclose

Elizabeth A. Morris MD, Abstract Co-Author: Nothing to Disclose

Breast cancer oncoplastic surgery allows a tandem approach to treatment and reconstruction, which may involve silicone implant placement. Postoperatively, magnetic resonance imaging (MRI) can diagnose silicone implant rupture. Enlarged internal mammary lymph nodes (IMLN) can develop after silicone implant placement but inaccessibility makes tissue diagnosis difficult. The purpose of this study was to assess among women with a history of breast cancer and silicone implant placement, the incidence of benign and malignant internal mammary lymph nodes on MRI.

This retrospective study received institutional review board approval and need for informed consent waived. Between 2000-2013, we identified women who had: a) breast cancer, b) oncoplastic surgery, c) postoperative implant protocol MRI. Clinical and pathologic data were collected. Short and long axis measurements of the largest IMLN, per side, were recorded. A benign IMLN was defined as having, at minimum, two years of either: 1) imaging stability and/or 2) no clinical evidence of recurrent disease. A malignant IMLN was defined if patient had biopsy proven metastatic disease.

956 women with breast cancer were identified who underwent oncoplastic surgery and a postoperative implant protocol MRI (n=552 bilateral and n=404 unilateral). The mean time between surgery and MRI was 84.4 months (range 0.5-512 months). 32 percent of patients (n=306) had IMLN. Mean short and long axis measurements were 0.5 cm (SD 0.2) and 0.7 cm (SD 0.3), respectively. ILMN were significantly more likely to be benign than malignant (p<0.05). Less than 5% of IMLN were metastatic.  

IMLN identified on silicone implant protocol breast MRI following oncoplastic surgery for breast cancer are significantly more likely to be benign than malignant. The results support imaging follow-up instead of immediate metastatic work-up

IMLN identified on implant protocol MRI are probably benign and imaging follow-up should be considered instead of an immediate work-up to exclude metastatic disease.  

Watson, E, Sutton, E, Gibbons, G, Morris, E, Incidence of Internal Mammary Lymph Nodes on Breast MRI Following Oncoplastic Surgery.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14045616.html