RESUMO
Primary signet-ring cell carcinoma (SRCC) of the breast is an uncommon variant, accounting for 2-4.5% of all primary breast cancers. Secondary SRCC of the endometrium is very rare and usually originates from the breast or gastrointestinal tract. A 54-year-old, postmenopausal woman with a past history of breast cancer four years previously was admitted with abnormal uterine bleeding. An endometrial biopsy revealed undifferentiated adenocarcinoma with signet-ring cells. The patient underwent laparotomy and cytoreductive surgery was performed. Pathological analysis and immunohistochemical tests demonstrated a uterine (endomyometrial) metastasis of breast SRCC. Omentum, peritoneal surfaces and retroperitoneal lymph nodes also included tumoral tissue with signet-ring cell morphology. The patient received adjuvant systemic chemotherapy with adriamycin, cyclophosphamide and paclitaxel. This case report discusses the patient's clinical characteristics and the role of cytoreductive surgery on patient survival in SRCC of the breast metastasizing to the uterus.