Should we perform mastectomy in case of CUP syndrome after risk-reducing mastectomy in patients with germline mutation?

Bilateral risk-reducing mastectomy (BRRM) is known to reduce the incidence as well as the mortality from breast cancer among patients at high risk. However, by total mastectomy all breast tissue can never be removed. How should we treat a patient with proven breast cancer in the axillary lymph nodes without having evidence for breast cancer in the reconstructed breast?

We present a case of a 32 year old woman with proven breast cancer in axillary lymph nodes after risk-reducing mastectomy and primary reconstruction with implants.

Patient concerns: At the age of 28 years the patient performed BRRM as skin-sparing mastectomy with primary implant reconstruction due to a BRCA 1 mutation. Four years after surgery the woman presented with enlarged axillary lymph nodes. CNB of the lymph node confirmed metastases of a triple negative breast cancer. Ultrasound und MRI imaging were not able to found any focus in the breast. One suspected area was biopsied without showing breast cancer. Neoadjuvant chemotherapy was performed after staging. Due to lack of evidence only axillary dissection with excision of the suspicious tissue in the breast was performed. Tumor stage after surgery: ypT0 ypN0 (0/12).

Summary:

For our case, no clear evidence exists. Further studies are needed to answer those special questions.