Breast cancer metastases to the stomach and colon mimicking primary gastrointestinal cancer: Four cases and literature review

Intraluminal gastric and colonic metastases of the breast cancer are very rare and may sometimes prove a  diagnostic dilemma to distinguish from primary gastric and colonic cancers. It is important to make the distinction in order to navigate the proper treatment approach, which is a systemic treatment rather than surgery if the disease is me- tastatic. The spread to the gastrointestinal (GI) tract is more frequent in lobular histology and according to a number of investigators, it is related to a particular tropism of lobular cells toward gastrointestinal mucosa. Any region of GI tract may be involved, from the tongue to the anus. Over the last decade, among the 1,100 breast cancer cases registered at our institutions, we diagnosed four patients with breast cancer who had metastases to the stomach and/or colon and presented symptoms that simulated primary gastrointestinal cancer. A total of 84 out of the 1,100 patients experienced invasive lobular histology. Among the four patients with GI tract metastases, three were diagnosed with lobular hist- ology – two of whom had the signet ring cell subtype. The remaining patient was diagnosed with triple negative invasive ductal carcinoma; however, it clinically resembled invasive lobular carcinoma. Clinical and pathological features of these cases, as well as the review of related literature are discussed in this report.