[Thrombophlebitis in an Elderly Japanese Woman Treated with Tamoxifen for Breast Cancer].

In this study, we report the rare case of an elderly woman who developed thrombophlebitis after being treated with tamoxifen for breast cancer. She visited our department with a lump in her left breast. She underwent core needle biopsy, and she was diagnosed with breast cancer (invasive ductal carcinoma, ER- and PgR-positive, HER2-negative). We chose hormonal therapy because surgical treatment was deemed too invasive considering her general status. She was administered tamoxifen (20 mg/day) instead of an aromatase inhibitor in consideration of her osteoporosis. Six months after initiating tamoxifen therapy, she exhibited swelling in her left leg. Computed tomography and ultrasound revealed thrombophlebitis in her left femoral vein. She stopped taking tamoxifen and started warfarin potassium as thrombolytic therapy, after which thrombophlebitis was relieved. Advanced age may be a risk factor for thrombophlebitis associated with tamoxifen treatment; therefore, precautions should be taken accordingly.