A 59-year-old female patient underwent surgery for invasive lobular carcinoma of the right breast 12 years ago. The final diagnosis was invasive lobular carcinoma (T4N1M0 stage IIIB). She underwent chemotherapy, radiotherapy, and hormonal therapy after surgery. She had abdominal bloating and vomiting 12 years after surgery. Contrast-enhanced computed tomography (CECT) and esophagogastroduodenoscopy showed edematous thickening from the stomach to the duodenum and moderate amounts of ascites. Lymph node metastasis was not observed. Biopsy specimens of the stomach revealed signet ring cell carcinoma. Immunochemical studies (ER, GCDFP-15, MUC1, MUC5AC, and MUC6) confirmed gastroduodenal metastasis of invasive lobular carcinoma. Ascites disappeared after she underwent chemotherapy with paclitaxel and bevacizumab; however, wall thickening had spread from the lower esophagus to the stomach, small intestine, colon, and rectum on the CECT. She died 7 months after the diagnosis of gastroduodenal metastasis. Herein, we report a case of invasive lobular carcinoma of the breast with extensive digestive tract metastasis.