[A Case of Metastatic Breast Cancer with BRCA1 Mutation after Breast Reconstruction and Pregnancy].

We present the case of a 31-year-old woman with a chief complaint of a left breast mass. The patient visited our department for an evaluation of this left breast mass. Left breast cancer(cT1cN0M0, cStage Ⅰ, triple negative type)was diagnosed, and left partial mastectomy and sentinel node biopsy were performed. Although the pStage was the same prior to surgery, a BRCA1 mutation was identified on genetic testing. After administration of postoperative adjuvant chemotherapy (epirubicin, cyclophosphamide, and paclitaxel), consorted mastectomy, tissue expander insertion, and breast reconstruction with silicone implant were performed. Spontaneous pregnancy occurred 1 year and 10 months after the first operation. She had an uneventful delivery with a normal course of labor 2 years and 6 months after the surgery. Two years and 11 months after the first operation, she visited our institution with complaints of headache, dizziness, and difficulty eating. Upon assessment, brain, lung, liver, and bone metastases were identified on contrast-enhanced computed tomography. Concentrated glycerin and fructose, steroid administration, and whole-brain irradiation improved the symptoms due to cerebral edema. Thereafter, olaparib was started, and treatment was continued while maintaining partial response(PR).