Gastric carcinoma metastatic to the breast.

A patient with signet ring adenocarcinoma of the stomach with metastatic disease to the breast treated at our institution is presented and added to the 14 cases reported in the literature. A review of the common clinical features and possible mechanisms of metastases is given. While the majority of patients present with symptoms referable to their gastric malignancy, the patient in this case initially sought treatment because of her breast mass. Metastatic deposits within the breast may be difficult to distinguish from primary breast carcinoma. For this reason, immunohistochemistry utilizing carcinoembryonic antigen (CEA), C-ERB B-2, and gross cystic protein were used in this case to confirm an extramammary source. In order to prevent unnecessary breast surgery and provide proper treatment of the gastric primary, the patient's complete clinical presentation must be used to guide diagnostic evaluation.