Metastatic breast carcinoma presenting as endometrial cancer. A case report.

Background: Breast cancer is the most common cancer in women in the United States and second leading cause of cancer death in women. Primary breast carcinoma frequently metastasizes to the pelvic organs.

Case: A 63-year-old, post-menopausal woman with a history of breast carcinoma presented with post-menopausal vaginal bleeding. Diagnostic studies were consistent with a fibroid uterus and notably normal ovaries bilaterally. Dilatation and curettage revealed poorly differentiated adenocarcinoma thought to be primary endometrial cancer. A total abdominal hysterectomy and bilateral salpingooophorectomy were performed, and final pathology revealed metastatic breast carcinoma. Neoplastic cells were strongly positive for both carcinoembryonic antigen and gross cystic disease fluid protein, a marker of breast carcinoma.

Conclusion: Breast carcinoma may metastasize to unusual sites, such as the endometrium and uterine leiomyomata, and mimic primary uterine malignancies. Immunohistochemistry is useful in reaching the diagnosis in difficult cases when a patient has a history of breast carcinoma.