Gastric Metastasis of Breast Cancer in a Male Patient: Report of a Case

Abstract

A 65-year-old male patient presented with epigastralgia. At 57 years of age, the patient was diagnosed as cancer of the right breast (T1cN0M0) and underwent a mastectomy and axillary dissection. ER and PgR were positive, and HER2 was 2+. At six years after surgery, multiple metastatic lung tumors were found to have developed, and the patient underwent a partial resection of the left lung. Supraclavicular and mediastinal lymph nodes and pleural metastasis also developed postoperatively and were treated with chemotherapy. The patient developed epigastralgia at 30 months after the lung surgery, and underwent upper gastrointestinal endoscopy. An elevated lesion with a bridging fold was detected in the middle body of the stomach, and the results of a biopsy showed adenocarcinoma. The immunohistochemical staining results were positive for cytokeratin (CK) 7 and negative for CK20, and the patient was diagnosed as breast cancer metastasis to the stomach. Although breast cancer metastasis to the stomach has been detected in a small percentage of cases based on autopsy findings, it is extremely rare that a diagnosis of this disease is made in the clinical setting. A case of breast cancer metastasis to the stomach in a male patient is even rarer. A search of the Japan Centra Revuo Medicina database revealed only one such case among previous reports in Japan. In conclusion, it is necessary to address the possibility of breast cancer metastasis to the stomach when searching for a gastric tumor in a patient with a past history of breast cancer.