Unusual Presentation of Gastric Outlet Obstruction Due to Breast Cancer Metastasis: A Case Report.

Gastric outlet obstruction can be caused by various pathologies, including peptic ulcer disease, gastric polyps, and malignancies. The incidence rate of breast cancer metastasis to the stomach is only 0.3%. We describe a rare case of an 83-year-old female with a remote history of breast cancer who presented with symptoms of nausea and vomiting. She underwent an upper endoscopy, and biopsies revealed chronic gastritis. However, when she presented for the second time with similar symptoms, she underwent endoscopic ultrasound (EUS)-guided biopsies, which clinched the diagnosis of breast cancer metastasis causing gastric outlet obstruction. This case describes the importance of keeping a wide differential diagnosis for the causes of gastric outlet obstruction and the significance of deeper EUS-guided biopsies if initial endoscopic biopsies are inconclusive.