Asymptomatic solitary metastasis to the stomach from breast cancer: A case report.

Distant metastases from breast cancer are frequently found in bones, lungs and the liver. Metastasis to the stomach is rare, and its clinical presentation remains unclear. The present report describes a case of isolated gastric metastasis from breast cancer identified by contrast-enhanced computed tomography (CT). A 45-year-old female patient underwent right mastectomy and axillary lymph node dissection after preoperative chemotherapy for right invasive lobular breast carcinoma T4bN2M0, stage IIIB. Postoperative radiotherapy and endocrine therapy with tamoxifen for 5 years were performed. CT for postoperative follow-up at 52 years old revealed thickening of the stomach wall. Although the patient was asymptomatic, erosive mucosa was observed on the gastric body during gastroscopy. The gastric lesion was immunohistochemically diagnosed as metastatic luminal disease from the breast cancer. Positron emission tomography/CT revealed no abnormal accumulation suggesting metastasis to other organs. Palbociclib and fulvestrant treatment were initiated for gastric metastasis. Invasive lobular breast carcinoma results in gastrointestinal metastasis, including the stomach, more frequently than invasive ductal breast carcinoma. However, most gastric metastases occur simultaneously with systemic metastases. Solitary metastasis to the stomach without symptoms as in this case has rarely been reported. The possibility of gastric metastasis should be considered among the differential diagnoses, even in the absence of symptoms, when gastrointestinal abnormalities are seen on CT in patients with a history of breast cancer.