Adenocarcinoma of the breast rarely metastasizes to the mucosal surfaces of the uterus. We present two patients with endometrial involvement, in one of whom it was the initial manifestation of her breast cancer. Two additional patients with cervical involvement had abnormal Papanicolaou smears and grossly normal cervices. One of these patients underwent a biopsy, the results of which confirmed metastatic adenocarcinoma. Three of the four patients had previously well-established metastatic disease. The presence of genital, especially mucosal, metastases is indicative of widespread disease and imminent demise. This occurred in one of the patients described here; however, another patient survived 30 months. Breast cancer is a chronic disease for which the metastatic behavior is exceptionally unconventional. Tissue acquired by endometrial curettage or colposcopy may require an awareness on the part of the pathologist to such a clinical circumstance.