Solitary mediastinal metastasis from breast cancer after 14 years: case report

Background: Mediastinal lymph node metastasis occasionally occurs in patients with advanced breast cancer, but cases of solitary metastasis are rarely reported. Case Description: A case of solitary mediastinal lymph node metastasis 14 years after breast cancer surgery is presented. A 50-year-old woman underwent a curative right mastectomy for breast cancer at 36 years old and a robot-assisted modified radical hysterectomy for cancer of the uterine body at 46 years old. Afterward, she received adjuvant chemotherapy and was followed up. After 14 years of mastectomy and 4 years of hysterectomy, she underwent an 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) scan to assess the status of her uterine body cancer during her follow-up. Accumulation of FDG was detected in the axillary lymph node and left middle mediastinal lymph node; however, it was not detected at any other site. Although malignant cells were not detected during axillary lymph node biopsy, there was a high suspicion of metastasis to the mediastinal lymph nodes, possibly originating from the breast or uterine body cancer. Then, she underwent mediastinal tumor resection by video-assisted thoracoscopic surgery (VATS) without complications. Malignant cells were detected after pathological examination, and immunohistochemistry revealed breast cancer metastasis. She had no recurrence 6 years after her surgery. Conclusions: Solitary mediastinal lymph node metastasis from breast cancer is rare. Moreover, our left middle mediastinal lymph node metastasis after right breast cancer is very rare. We speculated that the abnormal return of the thoracic duct and lymphatic network caused contralateral solitary mediastinal lymph node metastasis to a distant site.