Tuberous sclerosis is a hereditary disorder that presents with the classic triad of intelligence loss, seizures, and facial angiofibroma. The causative genes have been identified as the TSC1 gene on chromosome 9 and the TSC2 gene on chromosome 16.

　Since only a few cases of breast cancer occurring in tuberous sclerosis patients have been reported, we report this case with a review of the literature. We report a case of breast cancer that developed in a patient with tuberous sclerosis.

　A 44-year-old female patient was diagnosed with tuberous sclerosis at 6 years old. Her right kidney was removed due to the rupture of a renal angiolipoma at 26 years old, and she started haemodialysis due to renal failure at 42 years old. After examining a rapidly growing left breast mass, we diagnosed the patient with left breast cancer. We performed a left mastectomy and axillary lymph node dissection, and the pathological diagnosis was breast cancer pT3N1M0 pStageⅢA ER0% PgR0% HER2 (0) MIB-1 90%. We initiated postoperative adjuvant therapy, but rapidly increasing local recurrence was observed during the adjuvant therapy period, and recurrent tumors reached the pericardium. Local radiotherapy and chemotherapy were performed, but the treatment was ineffective. The patient died approximately 7 months after the initial surgery.

　Though we experience risk-reducing mastectomy (RRM) increasingly as a practice of HBOC is spread, evidences concerning RRM for patients with prior gynecologic cancers relating to HBOC (ovarian, fallopian tube and peritoneal cancers) are still poor. We present a 65-year-old woman with BRCA2 pathogenic variant, diagnosed as right breast cancer two years after the surgery of previous peritoneal cancer. She selected concurrent contralateral RRM and breast reconstructions through the genetic counseling. BRCA1/2 pathogenic variant carriers affected by ovarian cancer have generally poor prognosis and some authors warranted the survival benefit by RRM for these patients were restricted. On the other hand, the treatment by PARP inhibitor provides the survival improvement for these patients in recent years. We have to construct guidelines to consider which prophylactic intervention, RRM or imaging surveillance, is preferred for each patient. In this study, we focus on the management of the breast for patient involved with gynecologic cancers relating to HBOC.

　We experienced a case in which a mother was diagnosed with Lynch syndrome after genetic counseling following the diagnosis of breast cancer.　A 48-year-old woman visited our department for a left breast mass and was diagnosed with left breast cancer by close examination. She was then hospitalized for surgical purposes. A more detailed family history interview by a certified genetic counselor revealed a family history of colorectal cancer among many members in her maternal lineage that could not be obtained by the interview at the first visit. Because of suspected Lynch syndrome, the patient's mother underwent genetic testing after genetic counseling. As a result of the examination, a pathological mutation of MSH2 was found, which led to the diagnosis of Lynch syndrome. No pathogenic mutation in MSH2 was found in the patient. It was suggested that detailed family history interviews could lead to the diagnosis of hereditary diseases in families.

　Neurofibromatosis Type I (NF1) is known to cause multiple neurofibromas, however it rarely causes malignant peripheral nerve sheath tumor (MPNST). We experienced a patient with MPNST and single lung metastasis, therefore, I report this case. A 71-year-old woman, who had been clinically diagnosed with NF1, developed MPNST in July 2013. She received tumor resection three times (July 2013, March 2017, and March 2018). She was admitted to our hospital because of the enlarging lung tumor over 4 months. Bronchoscopic biopsy revealed the tumor was MPNST. Complete resection of the lung metastasis and the recurrence tumor on the back were performed consecutively.We experienced a case of lung metastasis from MPNST on the back which was diagnosed with bronchoscope and resected completely. As MPNST is resistant to both chemotherapy and radiotherapy, it was suggested that the radical resection of metastasis might be most effective treatment based on our case who has achieved long survival due to the early detection and the repeated operation. Early detection and radical resection of metastatic tumor may attribute to the long survival for the treatment of recurrent MPNST.

　The acquisition of reversion mutations is currently attracting attention as a key resistance mechanism to PARP inhibitors in BRCA-mutant cancer. We report a case of BRCA2 mutation-positive metastatic breast cancer tolerance to PARP inhibitors after long-term remission maintained with platinum-based chemotherapy. A 53-year-old woman diagnosed with triple negative breast cancer (cT1cN0M0 stage I) underwent surgery. Local recurrence was observed 4 years and 10 months postoperatively, followed by a relapse of the axillary, pulmonary, and chest wall metastases. Suspecting hereditary breast cancer ovarian cancer syndrome (HBOC), she was successfully treated with carboplatin-based chemotherapy, and had remained in remission for 5 years and 4 months. However, liver and bone metastases appeared 11 years and 7 months after surgery. At this point, national health insurance started to cover the BRCA test as a companion diagnosis for Olaparib in Japan, and she was positive for a BRCA2 mutation. Then, Olaparib was initiated, however, she subsequently died with little therapeutic effect.

　Risk-reducing salpingo-oophorectomy (RRSO) is the most reliable method to prevent ovarian cancer for patients with hereditary breast cancer ovarian cancer syndrome. However, there are some requirements to perform RRSO, and it is necessary to develop the infrastructure to provide RRSOs in medical institutions. Until now, no medical institution in Miyagi Prefecture has performed RRSO. Therefore, RRSO was introduced in our hospital. As a result, six patients underwent RRSO. We review the process leading to the implementation of RRSO in one case in which occult cancer was found, and discuss the significance and challenges of introducing RRSO in our institution.