Gastric metastasis from breast cancer: a pitfall in gastric biopsy specimens

A 49-year-old woman presented with abdominal discomfort and weight loss. Gastroduodenoscopy showed small polypoid lesions and biopsy specimens suggested primary adenocarcinoma with neuroendocrine differentiation. As the patient had a prior history of metachronous breast cancer, it was concluded that the case was metastatic carcinoma from the breast. The usefulness of a panel of selected immunohistochemical markers to determine the primary site of the breast in an appropriate clinical setting is greatly emphasized.