Gastric Metastasis of Ductal Breast Cancer – a Diagnostic Challenge

Abstract

Purpose: 1. Consider breast cancer (BRCA) metastases in BRCA patients with an apparent primary gastric cancer 2. Recognize the importance of histopathologic and immunohistochemical analysis in diagnosis of BRCA metastases to stomach Methods: A 48 year old female was evaluated for burning epigastric discomfort of several months' duration. Medical history was remarkable for gastroesophageal reflux disease (GERD) resistant to proton pump inhibitors and 6-year history of metastatic BRCA status post surgery and chemotherapy. Biopsy of red, ulcerated lesion on gastric mucosa suspicious for gastric carcinoma revealed epithelial cells consistent with ductal BRCA. Patient was diagnosed to have gastric metastases from BRCA and referred to her oncologist for further management. Results: Gastric metastases have been reported in 2–18% of cases of BRCA. The median time interval between diagnosis of BRCA and occurrence of gastric metastases is about 5 years (2–30 years). The clinical presentation of BRCA metastases is often indistinguishable from primary gastric cancer due to non-specific symptoms. Majority of cases (83%) are due to invasive lobular BRCA, rest are from ductal cancer. Linitis plastica (most common), discrete nodules and external compression patterns are seen on gross pathology. BRCA metastases and primary gastric cancer are indistinguishable by gross endoscopic findings or radiography. Definitive diagnosis requires endoscopy-guided deep and extensive biopsies of suspicious lesions followed by histologic comparison with primary BRCA specimen. However, lobular BRCA may produce a signet ring morphology which may be confused with primary signet ring or diffuse-type gastric adenocarcinoma. Detailed immunohistochemical analysis will differentiate metastatic BRCA from primary gastric carcinoma in such cases. The absence of E-cadherin (seen in gastric cancer), the presence of ER-alpha (estrogen receptor alpha) receptors and positive monoclonal staining with GCDFP-15 (gross cystic disease fluid protein-15 – a protein found in breast cyst fluid and in plasma of patients with BRCA) support the diagnosis of BRCA metastases. Hormonal/chemotherapy are mainstay of treatment. Conclusion: Gastric metastasis of BRCA should be considered in BRCA patients with suspicious looking gastric lesions. This condition may be missed due to clinical presentation and similarity of histology with primary gastric cancer. Immunohistopathology is essential to guide proper diagnosis of BRCA metastases and avoid unnecessary surgery