Metastatic breast cancer from gastric and ovarian cancer, mimicking inflammatory breast cancer: report of two cases.

Breast metastases from extra-mammary malignancies, especially those mimicking primary inflammatory breast carcinoma, are extremely rare. We report here two cases of inflammatory breast metastases from gastric or ovarian cancer. Both patients, who had prior advanced malignant disease, presented with unilateral breast redness and swelling with peau d'orange sign, resembling primary inflammatory breast cancer or acute mastitis. Breast biopsy revealed poorly differentiated adenocarcinoma with signet-ring cells or clear cell carcinoma in the lymphatic vessels and the parenchyma without an in situ lesion, similar to primary lesions of the stomach or ovary, respectively. Immunohistochemical staining for estrogen receptor, progesterone receptor, and gross cystic disease fluid protein 15 was of value for correct diagnosis. Since breast metastasis is a sign of poor prognosis of the primary malignant disease, the possibility of breast metastasis should be considered in appropriate patients to preclude unnecessary major surgery.