The incidence of gastrointestinal metastases from breast cancer (BC) is low. We report a special case of Luminal B (Hormone Receptor positive [HR+]/Human Epidermal Growth Factor receptor 2-positive [HER-2+]) BC. The patient presented with asymptomatic brain metastases two years after radical surgery for modified breast cancer and developed right lower abdominal pain during relief therapy. Electronic gastroenteroscopy revealed inflammatory changes in the cecal mucosa. These changes were confirmed on pathology to be cecal metastasis from BC. The patient's condition was stabilised after treatment with an antibody-drug conjugate (ADC). For patients with BC who develop appendicitis-like symptoms after treatment for invasive ductal carcinoma of the breast, clinicians should be fully aware that the possibility of cecal metastasis needs to be considered, despite the very low probability of occurrence.
Keywords: Breast Cancer; Case Report; Cecal Metastasis; Gastrointestinal metastases; Invasive Ductal Carcinoma.