Breast cancer metastasis to the stomach may mimic primary gastric cancer: report of two cases and review of literature

BACKGROUND: The stomach is an infrequent site of breast cancer metastasis. It may prove very difficult to distinguish a breast cancer metastasis to the stomach from a primary gastric cancer on the basis of clinical, endoscopic, radiological and histopathological features. It is important to make this distinction as the basis of treatment for breast cancer metastasis to the stomach is usually with systemic therapies rather than surgery. CASE PRESENTATIONS: The first patient, a 51 year old woman, developed an apparently localised signet-ring gastric adenocarcinoma 3 years after treatment for lobular breast cancer with no clinical evidence of recurrence. Initial gastric biopsies were negative for both oestrogen and progesterone receptors. Histopathology after a D2 total gastrectomy was reported as T4 N3 Mx. Immunohistochemistry for Gross Cystic Disease Fluid Protein was positive, suggesting metastatic breast cancer. The second patient, a 61 year old woman, developed a proximal gastric signet-ring adenocarcinoma 14 years after initial treatment for breast cancer which had subsequently recurred with bony and pleural metastases. In this case, initial gastric biopsies were positive for both oestrogen and progesterone receptors; subsequent investigations revealed widespread metastases and surgery was avoided. CONCLUSION: In patients with a history of breast cancer, a high index of suspicion for potential breast cancer metastasis to the stomach should be maintained when new gastrointestinal symptoms develop or an apparent primary gastric cancer is diagnosed. Complete histopathological and immunohistochemical analysis of the gastric biopsies and comparison with the original breast cancer pathology is important.