A Case of Occult Cancer Detected after Risk-reducing Mastectomy in a BRCA2-positive Patient who Had Not Yet Developed Breast Cancer

Abstract

The patient was a 50-year-old woman she was followed-up for 16 years after mastopathy in the C region of the right breast at our hospital. Two years prior, her sister underwent genetic testing for heterochronous bilateral breast cancer. She tested positive for the BRCA2 gene mutation. The patient underwent genetic testing and BRCA2 gene mutation was positive. Because the patient wanted risk-reducing surgeries, we performed preoperative imaging evaluations. MRI and ultrasonography revealed diverse findings in both breasts. Needle biopsy was performed because of lesions suggestive of malignancy in the C regions of the right breast and the A region of the left breast. No malignancies were found. A mass shadow was observed in the D region of the left breast. Since there was no imaging evidence suggesting malignancy and the tumor had been present for 12 years, a needle biopsy was not performed. The patient underwent risk-reducing mastectomy and risk reducing salpingo-oophorectomy. Pathology examination showed a 7 mm invasive ductal carcinoma (occult cancer) in the D area of the left breast. Here, we report a case of occult cancer after risk-reducing mastectomy in a BRCA2-positive patient who had not yet developed breast cancer.