Uterine
metastases from
breast cancer are uncommon and have rarely been reported in the previous literature. The present report describes the case of a 66-year-old female who developed uterine
metastasis 23 years following the primary treatment of invasive
breast cancer. Specifically, the patient experienced multiple bone
metastases 14 years following primary treatment and had previously been treated with
aromatase inhibitors followed by
tamoxifen citrate. The patient presented with abnormal genital
bleeding and was referred to the Gynecology Department of the Osaka City University Hospital (Osaka, Japan) 23 years following the primary treatment. The results of an endometrial biopsy revealed
adenocarcinoma. Initially, it was difficult to differentiate between primary endometrial
adenocarcinoma and metastatic
adenocarcinoma from
breast cancer. The results of pelvic magnetic resonance imaging demonstrated uterine myometrium enlargement and no endometrial thickness. Furthermore, an abdominal total
hysterectomy, bilateral
salpingo-oophorectomy and a biopsy of the peritoneum were performed. The pathological examination of the resected uterus revealed
adenocarcinoma, which proliferated diffusively in the cervical stroma, myometrium, cardinal ligament, bilateral adnexa, omentum and peritoneum. Immunohistochemical results revealed the positive staining of gross cystic disease fluid protein-15, as well as negative staining for CD10 and
E-cadherin. Thus, the
tumor was diagnosed as metastatic
adenocarcinoma from the breast
lobular carcinoma. The patient has since been treated with
fulvestrant,
toremifene citrate and
tegafur, and the current patient survival duration is 2 years and 8 months. In conclusion, when patients with
breast cancer undergoing hormonal
therapy, such as
tamoxifen, present with abnormal genital
bleeding, future diagnoses should consider both
endometrial cancer and uterine
metastasis from
breast cancer.