Gastrointestinal: Gastric Metastasis From Breast Cancer With Minimal Endoscopic Changes

Breast cancer is one of the commonest tumors responsible for gastrointestinal metastases. The most common endoscopic finding is diffuse intramural infiltration imitating linitis plastica [1]; however, few reports to date have provided endoscopic images of gastric metastasis of breast cancer in its early stages. A 70-year-old woman presented to our hospital with abdominal pain. She had been diagnosed with breast cancer 2 months previously and had received chemotherapy 2 days before presentation. Upper gastrointestinal endoscopy revealed an elevated lesion with a small depression in the gastric antrum (Figure 1a). In addition, multiple discolored lesions 2 mm in size were observed in several areas, including the anterior wall of the upper gastric body and the greater curvature of the lower gastric body (Figure 1b,c). Magnifying endoscopy with narrow-band imaging revealed minute discolored lesions with a clear demarcation line and irregular microvascular pattern (Figure 1d). We performed endoscopic submucosal dissection of the elevated lesion, and biopsies were taken from several other discolored lesions to confirm the diagnosis. All samples were found to be poorly differentiated adenocarcinoma (Figure 2a). Immunohistochemically, the tumor cells were positive for estrogen receptor and GATA3, with reduced E-cadherin staining (Figure 2b), consistent with the primary tumor's histological characteristics of invasive lobular carcinoma. Notably, most of the discolored lesions gradually shrank following the initiation of hormone and targeted therapy for breast cancer (Figure 2c,d). Gastric metastases have been recognized in 8.9% of cases of breast carcinoma, and the most common histological type that tends to metastasize to the gastrointestinal tract is invasive lobular carcinoma [1, 2]. In our case, multiple metastases were recognized as minute discolored mucosal lesions, along with elevated lesions as in early gastric cancer, and were considered to be endoscopic findings that captured the very early stage of multiple gastric metastases from breast cancer. This case highlights the usefulness of narrow-band imaging in the early diagnosis of metastatic gastric cancer that showed minimum change as observed by white-light endoscopy. The authors declare no conflicts of interest.